SingleCase Outlook Add-in

The SingleCase Outlook Add-in connects Outlook to SingleCase. It lets you save emails and their attachments to the right case without leaving Outlook.

The add-in opens as a panel on the right side of Outlook. You can use it in two ways:

• When you open an email (read mode): the add-in checks whether the email is already filed, suggests the likely case, and files the email with the attachments you choose.
• While you write an email (compose mode): you choose the case before sending, and the add-in files the email when you click Send, automatically or after you confirm.

The add-in works in Outlook for Windows, Outlook for Mac and Outlook on the web. Check which versions are supported in Supported platforms.

Before you can use SingleCase, the add-in needs to be in your Outlook. There are two ways this can happen:

Or install it yourself (public version — available in the Microsoft AppSource marketplace):

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New Outlook for Mac required. SingleCase does not work in Legacy Outlook for Mac. If you still use it, switch off the Legacy Outlook toggle in Outlook first. See Supported platforms.

1. Open Outlook and go to Tools menu → Get Add-ins.

2. The Add Apps dialog opens. Type SingleCase in the search box and press Enter.

3. Click Add next to the SingleCase listing.

4. The add-in is installed. SingleCase will appear under Built for your org and the button will show in your ribbon the next time you open an email.

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If the SingleCase button does not appear in the ribbon after installation

You can add it manually using the Customise Toolbar option:

1. Click the … (three-dot overflow menu) at the right end of the ribbon and choose Customise Toolbar…

Click … in the ribbon, then choose Customise Toolbar…

2. In the Customise Toolbar dialog, find SingleCase under Installed Add-ins on the right-hand side, then drag and drop it into the main toolbar area on the left.
3. Click Done to save your changes.

Drag SingleCase from the Installed Add-ins list into the toolbar to pin it to the ribbon.

First Time Open

You only need to do this once. After setup the add-in keeps you signed in automatically.

1. Enter your workspace URL. On the welcome screen, type your SingleCase workspace address (for example yourfirm.singlecase.app). If you are unsure of your address, click Open workspace to look it up in your browser.

   

   Enter your workspace address on the welcome screen.

2. Microsoft sign-in (may appear once). A Microsoft sign-in window may appear briefly — no action needed, it resolves automatically.

   

   Microsoft sign-in prompt.

Staying signed in

The add-in uses the same account you already use for Outlook. As long as you are signed into Outlook, you are signed into SingleCase too — no password, no extra steps required.

You may be prompted to sign in manually in the following situations:

• You are using an older version of Outlook that does not support silent login. In that case, a button will appear — click it to log in via a popup:Sign in with Microsoft
• Your organisation requires additional consent for a new permission. A message will guide you through the one-time step.

Switching workspaces

To connect to a different SingleCase workspace, open Settings, click Change workspace and enter the new workspace address.

The SingleCase add-in requires Outlook connected to Exchange Online (Microsoft 365 subscription or Exchange Online standalone). On-premises Exchange is not supported.

The add-in files the email you have open: a received email from your inbox, or an email you sent, from Sent Items. It always files that one email, not the whole conversation. If you need other emails from the same thread in SingleCase, file each of them separately.

1. Open the email you want to file, in your inbox, Sent Items or any other folder.

2. Open the SingleCase panel from the ribbon, if it is not open yet (see Open the add-in).

3. Check what the panel says. The add-in first checks whether the email has already been filed.

   • Already filed: the panel shows the case and the filed documents. There is nothing more to do.
   • Not filed yet: the panel asks “This email isn’t filed yet. Do you want me to file it?” Click Yes, file it.
   

   The add-in asks whether you want to file the email.

4. Select the case. Suggested cases appear at the top of the list, and you can search for any other case. See Finding a case and Case suggestions.

   

   Search for a case by client, name or number.

5. Choose what to file. Select the attachments, the destination folder and, if needed, new file names. See Choose attachments, folder and name.

   

   Select the attachments to file with the email.

6. Click Continue. The add-in uploads your selection to SingleCase and shows a summary. The email in Outlook gets the SC: Filed label. See After filing.

After you select a case, the add-in shows what will be filed. The email itself is always filed, as an .eml file. If the email has attachments, you can also choose which of them to file, rename them and choose the folder they go to. If the email has no attachments, these options do not appear and Continue files the email straight away.

Choosing attachments

Under Attachments to include, every attachment has a checkbox and all of them are selected by default. Uncheck the ones you do not need. When an email has more than one attachment, Select all / Deselect all switches them all at once. You can file up to 50 attachments from one email.

When you are ready, click Continue.

Renaming an attachment before filing

Attachments often arrive with names that mean nothing inside a case, such as scan0001.pdf or IMG_4821.jpg. You can rename an attachment before it is filed, so it lands in SingleCase under a name your colleagues will recognise.

1. Click the pencil icon next to the attachment.

   

   Click the pencil icon next to an attachment to rename it.

2. Type the new name and press Enter, or click outside the field. Press Esc to discard the change.

   

   Only the name can be changed. The extension stays as it is.

3. Click Continue. The attachment is filed under the new name, and the add-in shows that name whenever you open the email again.

   

   The filing summary shows the document under the name you gave it.

• The extension cannot be changed, so a .pdf stays a .pdf.
• An empty name changes nothing. The attachment keeps its original name.
• Two attachments with the same name cannot be renamed. Their pencil icon is disabled and shows “An attachment sharing its name with another one cannot be renamed”.
• The email in Outlook is untouched. Only the copy in SingleCase gets the new name.

Choosing the destination folder

Below the attachments is a Folder row with two options:

• Default (preselected): the attachments go to the case’s default folder for incoming mail, Correspondence → Incoming.
• Custom: you choose any folder in the case.

With Custom, the case’s folders appear below the row. Click a folder to open it. The folder you are in is the selected one: it is shown at the top of the list with a checkmark (✓). Folders that contain subfolders show an arrow (→). To go one level up, click the selected folder at the top of the list (↵).

The checkmark shows the folder the attachments will be saved to.

Once filing is complete the panel shows a summary:

The summary view after a successful filing.

• The case name (click it to open the case in SingleCase)
• The date and time it was filed
• The number of documents filed
• Each filed document listed individually

From the summary you can also manage each document:

Where to find everything in SingleCase

Once filed, you can find the email and attachments directly in the case in SingleCase.

The email — Case Mailbox

The filed email appears in the Case Mailbox of the case.

The filed email is visible in the Case Mailbox.

Attachments — Documents

Any attachments you selected are stored in the Documents section of the case. With the default folder setting they land in the case Inbox, under Correspondence → Incoming. If you picked a different folder before filing (see Choosing the destination folder), you will find them in that folder instead.

Filed attachments appear in Documents under Correspondence → Incoming.

When you open an email, the add-in first checks its status in SingleCase. Depending on the result, the panel shows one of the following.

Already filed

The panel shows the case and the filed documents. This works the same whether you filed the email yourself, a colleague filed it, or it was filed on send. The email also gets the SC: Filed label in Outlook. See After filing for what you can do from here.

Not filed yet

The panel asks “This email isn’t filed yet. Do you want me to file it?”

• Yes, file it opens the case selection. See File an email.
• No leaves the email unfiled. The panel confirms “Got it. I won’t file this email now.” and does not ask about this email again until the panel is reopened.

Internal emails

If the sender and all recipients are from your organisation’s email domain (including its subdomains), the panel asks “This looks like an internal email. Mark as Skipped?” This detection is automatic; there is no setting for it.

• Yes marks the email as skipped. It gets the SC: Skipped label and the panel says “Marked as Skipped. You can still file it manually.”
• File anyway opens the case selection, the same as for any other email.

Skipped emails

When you open an email marked as skipped, the panel says “This email has been marked as skipped. You can still file it manually.” Click File manually to file it to a case.

Removed from SingleCase

If the email was filed but its documents were later deleted in SingleCase, the panel says “This email was removed from SingleCase. Do you want to file it again?” Click Yes, file it to file it again, or No to leave it.

Filing the same email again

If you file an email that is already filed, the panel says “This email was already filed. Click again to file anyway.” Click again only if you really want to file it a second time.

Filed emails normally stay in your inbox with only the SC: Filed label. If you prefer a clean inbox, the add-in can move each email you file into a folder for its case, right after filing.

Turning it on

1. Open Settings (the gear icon in the add-in panel).

2. In the Email organization section, switch on Move filed emails to a folder in Outlook. The helper text below it reads: “After you file an email in SingleCase, the plugin automatically moves it to the SingleCase - Plugin → [case name] folder in your Outlook.”

The setting is saved for you and stays on when you close and reopen the add-in. Switching it off again stops future moves; emails already moved stay in their case folders.

How the folders are organised

The add-in creates a folder named SingleCase - Plugin at the top level of your mailbox, next to your Inbox. Inside it there is one folder per case, named case number · case name:

SingleCase - Plugin
  2024-0003 · Environmental protection
  2025-0010 · Smith vs. Jones
  2026-1348 · Flat-fee retainer

• Both folders are created automatically: SingleCase - Plugin the first time an email is moved, and a case folder the first time you file an email to that case.
• If a case has no case number, the folder is named after the case name only.
• The characters /, \ and : in case names are replaced with a hyphen, and very long names are shortened.
• The folders live in your mailbox, so you see them in Outlook on all your devices.

Which emails are moved

• Only emails you file with the add-in, at the moment you file them. No other email in your mailbox is ever touched.
• The email is moved, not copied. It disappears from the folder it was in and appears in the case folder, still with the SC: Filed label.
• Emails filed before you turned the setting on stay where they are. Nothing is moved retroactively.

If the email cannot be moved

Filing always comes first. If the move fails, the email is still filed in SingleCase, it stays in its original folder, and the add-in lets you know. You can then move it yourself.

Renaming, moving or deleting the folders

The add-in looks for a case folder by its name inside SingleCase - Plugin (upper and lower case do not matter). If you rename a case folder, move it somewhere else or delete it, the next email you file to that case creates a new folder with the standard name. The same applies to the SingleCase - Plugin folder itself.

With File on Send, you choose the case while you are writing the email. After you click Send, the add-in files the sent email to that case for you, either automatically or after you confirm it, depending on your settings. There is no need to go to Sent Items afterwards.

While you write, the panel shows the case and what happens after you click Send.

Choose how File on Send behaves

Open Settings in the add-in (see All settings explained) and choose one of the options under File on send:

Choose the behaviour under File on send in Settings.

With Always file, the panel turns green once a case is selected.

How to use it

1. Open a new email or a reply and click the SingleCase button in the ribbon to open the panel. The case has to be selected in the panel before you send. If you send without opening the panel, nothing is filed on send and you can file the email later from Sent Items.

2. Add a recipient. Until there is at least one recipient in To or Cc, the panel shows “Add a recipient (To / Cc)”. If you send the email to a case’s SingleCase email address, the case is recognised straight away.

   

   Until the email has a recipient, the panel asks you to add one.

3. Check the case. The panel names the case the email will be filed to. If it is not the right one, click Select a different case and pick another from the list or search for it. If the add-in has no suggestion, the panel says “Select a case for this draft.” Click Select a case and choose one.

   

   No suggestion yet: click Select a case.

4. Keep writing or close the panel. The selected case stays with this draft until you send it.

5. Click Send. The email always goes out. With Always file, it is filed in the background. With Warn each time, the add-in asks you about it the next time you open the panel.

How the add-in picks the case

While you write, the add-in decides which case to prepare in this order:

• A case you chose yourself always wins.
• Case email address in the recipients: if you send the email to a case’s SingleCase email address, that case is selected.
• Recognised automatically: when the email belongs to a thread that is already filed, the subject or body contains the case number, or a recipient’s address matches the case exactly, the case is selected and the panel shows “Suggested case: …”.
• Recipients you have filed with before: if you previously filed emails with the same people to a case, that case is offered in the list under Select a different case. It is not selected for you.

In the list under Select a different case, each suggestion shows why it was offered, for example “Same email thread”, “Case number in the email”, “You often file this sender here” or “Recently used case”.

More about how cases are ranked in Case suggestions, and about case addresses in Send to a case email address.

What gets filed?

The sent email is saved as a document to the root of the selected case’s documents. Attachment selection, the destination folder and renaming (see Choose attachments, folder and name) are not available with File on Send. If you need them, do not select a case in the draft, and file the email manually from Sent Items after sending (see File an email).

If the panel says “After sending, you can file it from the Sent folder.”, the add-in could not prepare this draft for filing. The email sends normally, but nothing is filed on send; file it manually from Sent Items.

File on Send vs. manual filing

Every case in SingleCase has its own email address in the format CASE-ID@yourfirm.singlecase.app. When you add this address to the recipients of an email you are writing, usually as Bcc so the other recipients do not see it, the add-in recognises the case straight away.

• The case is selected in the panel without any searching, and the panel names it.
• A case address is treated as certain. It is used ahead of any suggestion; only a case you pick yourself takes priority.
• What happens after you click Send depends on your File on Send setting.

The outcome is shown at the top of the add-in panel the next time you open it, whichever email you have selected:

• Filed: “Sent message filed to [case].” The message stays until you close it. Click Change case to open the case in SingleCase if the email went to the wrong case; the add-in cannot move a filed email to another case.

  

  The confirmation stays until you close it.

• Already filed elsewhere: if the same email is already filed in a different case, it is not filed again and the message names the case where it already is.
• Failed: “Filing failed. Reopen the add-in or file manually.” This appears when filing cannot succeed, for example when you do not have permission to file to the case or your Microsoft sign-in has expired. Temporary problems, such as a network outage, are not reported; the add-in simply tries again the next time you open the panel.
• Waiting for confirmation (Warn each time): if you do not answer the question, it comes back every time you open the panel for 24 hours. After that, the email stays unfiled. If you sent several emails, the add-in asks about them one at a time, oldest first.

  

  With Warn each time, the add-in asks before filing.

The case list has two views, switched with the buttons at the top: All and Favourites. Which one opens first is set in Settings (Default case group, All by default).

Searching for a case

In All, the add-in shows its suggested cases and a search box below them. Type at least 3 characters; results appear as you type, and more load as you scroll down. Each result shows the case name, the case number and the client. Press Enter to pick the first result, or Esc to clear the search.

You do not need to type full names; partial terms work, and you can combine them:

Favourites

Favourites lists the cases you starred in SingleCase. Suggestions and the search box are only shown in All; in Favourites you pick a case from the list.

Switch between All and Favourites with the buttons at the top of the list.

When you file an email you have open, the add-in asks SingleCase which cases the email most likely belongs to, and shows up to three suggestions above the search box (in All).

Suggested cases with their confidence and the reason they were suggested.

What a suggestion shows

• The case name, and below it the case number and the client.
• A confidence percentage.
• The main reason for the suggestion: “Same email thread”, “Case number in the email”, “You often file this sender here”, “Emails from this organisation are usually filed here”, “Linked contact”, “Recently used case” or “Suggested match”.

What the add-in looks at

SingleCase combines several clues. Each clue adds to a case’s score, so a case that matches several of them ranks higher. From strongest to weakest:

1. Same email thread. Another email from this conversation is already filed to the case.

2. SingleCase case number in the subject, the first 5,000 characters of the body, or an attachment name. It has to match as a whole number, not as part of a longer one.

3. Court file number in the same places. Separators do not matter, so 23-C-159, 23/C/159 and 23 C 159 all match.

4. Your history with these addresses. How often and how recently you filed emails with the sender and recipients to the case.

5. The organisation’s history. Emails from the same email domain filed to the case. This counts far less than an exact address, and less the more cases the domain is spread across. Your firm’s own domain and public domains such as gmail.com are ignored.

6. Linked contacts. A participant matches an active contact linked to the case in SingleCase. If the contact is linked to several cases, the boost is split between them, so a contact on many cases says little about any one of them. A contact linked to just one case ranks above weak sender history, but established history (frequent, recent filing) still wins.

7. Recently used cases. Cases you filed to in the last 14 days. This only decides between cases that other clues already surfaced.

A case or court number in the email always ranks above filing history alone.

The confidence percentage

The percentage reflects both how strong the clues are and how far the case is ahead of the next one. If two cases have equally strong clues, both get a lower percentage. A single clue, even an exact case number, does not reach 100%. Cases below 10% are not shown.

Recommended case

When the top case is clearly ahead, the add-in marks it as recommended with a green outline, and you can click Continue right away. Only the strong clues count towards this: the same thread, a case or court number, or your history with these addresses. The organisation’s history and linked contacts never make a case recommended on their own. Nothing is filed until you click Continue, and you can always pick a different case.

Suggestions are personal

Suggestions are based on the cases you have access to and on your own filing history, so a colleague can see different suggestions for the same email. Every email you file improves later suggestions for the same people and organisations.

The add-in uses Outlook categories to show the filing status of each email at a glance. These labels appear in your inbox, sent items, and any folder where the email lives, and sync across all your devices.

To open Settings, click the gear icon (⚙) in the top-right corner of the add-in panel. Close it with Done or the × in the top-right corner.

Click the gear icon to open Settings.

Settings in the add-in.

At the bottom of Settings:

• Version and Workspace show the add-in version and the workspace you are connected to. Include both when you contact support.
• Change workspace connects the add-in to a different SingleCase workspace. See Sign in and choose your workspace.
• Reset restores the default settings.

Filing emails

Cases and suggestions

Sign-in, updates and availability

How do I get the latest version of the add-in?

The add-in updates automatically. Because it runs as a web application inside Outlook, your administrator publishes new versions to Microsoft 365 and you always receive the latest release the next time you open Outlook. You do not need to install anything manually.

If you need to pick up a new version immediately without restarting Outlook, you can force-reload the add-in taskpane:

• Outlook for Mac: right-click anywhere inside the SingleCase taskpane → Reload.
• Outlook for Windows: right-click anywhere inside the SingleCase taskpane → Reload.
• Outlook on the Web (Mac): click inside the taskpane and press Cmd+Shift+R.
• Outlook on the Web (Windows): click inside the taskpane and press Ctrl+Shift+R.

Right-click inside the taskpane and choose Reload to pick up the latest version immediately.

You can check the installed version via Outlook: My Add-ins:

• Outlook on the Web: open any email → click the three-dot menu (⋯) → Get Add-ins → My add-ins. Find SingleCase in the list. The version is shown below the add-in name.
• Outlook for Mac: Tools menu → Get Add-ins → My add-ins tab.
• Outlook for Windows: File → Manage Add-ins (opens a browser page) → My add-ins tab.

When reporting an issue, include the version number from either location so your IT administrator or SingleCase support can assist you.

Coming in version 1.4

• Move filed emails to case folders. An optional setting that moves each filed email into a SingleCase - Plugin → case folder in Outlook. See Move filed emails to case folders.

Version 1.3.1.0 · October 2026

• New: File on Send. Choose the case while you write an email, and the add-in files it when you click Send, automatically or after you confirm. See File on Send.

Deploy SingleCase to your entire organization — or to specific users or groups. Requires a Global Administrator or Application Administrator account. Users receive the add-in automatically in their Outlook ribbon with no action on their side.

1. Sign in to the Microsoft 365 Admin Center at admin.microsoft.com.

2. In the left sidebar, go to Settings → Integrated apps.

3. Click Upload custom apps to deploy via manifest file, or search for SingleCase in the App Store and select it.

   • If uploading a manifest: select Office Add-in as the app type, then upload the manifest file.

4. In the Add users step, choose the deployment scope:

   • Just me — your account only (useful for testing)
   • Entire organization — all users in your M365 tenant
   • Specific users / groups — a defined list or security group

5. Click Deploy and confirm. Propagation can take up to 24 hours — in practice we typically see it within 12 hours.

6. The SingleCase button appears automatically in each assigned user's Outlook ribbon on their next launch.

Full step-by-step deployment guide with screenshots →

Updating the Manifest

If SingleCase provides a new manifest file (for example when switching from Trial to Production, or when the add-in URL changes), you replace it in the Admin Center without removing the existing deployment. Always-up-to-date manifest files are available in the IT Administrator Guide → Manifest files ↗.

1. Go to Settings → Integrated apps in the Microsoft 365 Admin Center and select the SingleCase add-in from the list. In the panel that opens, under Actions, click Update add-in.

   

   The add-in detail panel — click Update add-in under Actions.

2. On the Update file screen, keep Upload manifest file (.xml) from device selected, click Choose File and pick the new manifest. Wait for Manifest file validated to appear, then click Next.

   

   Upload the new manifest from your device — the green Manifest file validated confirmation must appear before you continue.

3. Review the Updates screen, which lists the app permissions and capabilities requested by the new manifest, then click Accept and update.

   

   Review the requested permissions and capabilities, then Accept and update.

4. The update runs. Update in progress… is shown while it completes — you can close the panel and it will continue in the background.

   

   The update is applied in the background.

5. Updated successfully confirms the new manifest is deployed. Click Done. User assignments carry over — there is no need to reassign anyone.

   

   Confirmation that the manifest has been updated for all assigned users.

Because SingleCase is deployed as a line-of-business (LOB) add-in, metadata changes require the admin to upload the new manifest as above — the add-in then updates the next time a user starts Outlook.