Outlook on Windows

This guide adds the TrustDID Outlook add-in on Windows. You'll end up with a TrustDID group on the ribbon — Sign Documents in the compose view and Verify Signatures in the read view — talking to the TrustDID service running on your own machine.

Requirement — a Microsoft 365 / Exchange mailbox. Outlook add-ins (this is a "web add-in") only load for Exchange Online / Microsoft 365 or on-premises Exchange accounts. They are not supported on POP/IMAP mailboxes — generic ISP or webmail accounts (e.g. most @videotron.ca, @gmail.com, cPanel hosting). On those accounts Outlook doesn't even show the "Add a custom add-in" option. If your mailbox isn't on Exchange/M365, use the CLI (trustdid sign / trustdid verify) or the Thunderbird/browser plugins instead.

Before you start

You need:

A Microsoft 365 / Exchange mailbox configured in Outlook (see the requirement above).
The TrustDID software bundle installed — run the setup.exe installer. On Professional and up it places the add-in files at C:\Program Files\TrustDID\outlook-plugin\. See Software Bundle on Windows if you haven't done that yet.
An activated identity — for paid tiers you've run trustdid-setup --managed YOUR_TOKEN YOUR_ID (token and UUID come from your enrolment email; it pulls your license automatically). Free-tier users get a public test identity. Confirm with trustdid status.
The TrustDID Service running — the installer registers it as a Windows service that auto-starts. Confirm with trustdid-service status.

The add-in talks to the service over https://localhost:8080 (API) and https://localhost:8000 (the add-in's pages). Both ports must be free.

Step 1: Verify the service is up

Open https://localhost:8080/health in a browser. Accept the local TrustDID self-signed certificate the first time — you should then see a small JSON response with "status": "ok".

If you get "connection refused", the service isn't running. Start it from a terminal:

trustdid-service status
            trustdid-service start

Step 2: Add the add-in to Outlook

The add-in is a small XML manifest that points at the service on your machine. The software-bundle installer already placed it here:

C:\Program Files\TrustDID\outlook-plugin\manifest.xml

Install it once per Outlook profile:

In Outlook, open Home → Get Add-ins (or File → Manage Add-ins), then choose My add-ins.
Scroll to Custom Addins and click Add a custom add-in → Add from File.... (If you don't see this option, your mailbox isn't an Exchange/M365 account — see the requirement at the top.)
Browse to C:\Program Files\TrustDID\outlook-plugin\manifest.xml and open it.
Confirm the warning prompt — click Install.

The TrustDID group with Sign Documents and Verify Signatures buttons now appears on the ribbon, in both the compose and read views.

Don't move or delete C:\Program Files\TrustDID\outlook-plugin\. Outlook loads the add-in's pages from there (through the local service) every time it runs, so the files must stay where the installer put them. If you instead downloaded the standalone TrustDID-Outlook plugin .zip, extract it to a permanent folder and point Add from File at that manifest.xml — same rule: don't move the folder afterward.

Step 3: Sign your first email

Click New Email.
Compose a short message. The TrustDID group is on the ribbon.
Click Sign Documents. A footer signature line is appended to the message, and your attachments are signed.
Send. The recipient gets the email plus a .vrfy sidecar.

Step 4: Verify a received email

Open a signed message and click Verify Signatures. The task pane shows a result within a second or two, answering two independent questions:

Document authenticity — "Is it genuine?" (Verified / Inconsistent / Failed / Unsigned)
Green shield — authenticity Verified: the signature verifies, the sender's DID is published, and the sender's email matches the From header.
Amber shield — the signature verifies but something else is off (for example the From header was rewritten by a mailing list).
Red shield — authenticity Failed, or the sidecar is missing (Unsigned).
Trusted signer — "Who vouches for it?" (Yes / No / Unknown) — based on the trust registries your verifier is configured with (trustdid-setup --add-trusted-registry). An authentic message from a signer none of your registries vouch for is a normal outcome — genuine, but untrusted until someone you trust vouches for the sender.

Click the shield for the full verification trace.

Troubleshooting

"Add a custom add-in" isn't in the menu. Your Outlook profile is a POP/IMAP account, which doesn't support add-ins. The add-in needs an Exchange Online / Microsoft 365 mailbox. Nothing you install locally changes this — it's an Outlook/Exchange limitation.

"Couldn't load the add-in" when installing. The TrustDID Service isn't running, or port 8000 is blocked. Check https://localhost:8000/commands.html in your browser — you should see a page, not an error. Start the service with trustdid-service start.

Sign button stays grey / does nothing. Identity isn't configured. Run trustdid status and trustdid-service status — they tell you whether the identity file is missing or the license is expired.

Verification task pane shows "service unreachable". The service stopped, or antivirus/firewall is blocking https://localhost:8080. Add an exception for C:\Program Files\TrustDID\.

New Outlook / Outlook on the web doesn't show the buttons. The local "Add from File" sideload works in classic Outlook desktop. For new Outlook and Outlook on the web, add-ins must be deployed by your Microsoft 365 admin (Integrated Apps / Centralized Deployment) or published to AppSource — a local manifest can't be sideloaded there. Contact us if you need the admin-deployment package.

What's installed

The software-bundle installer lays the add-in down here:

C:\Program Files\TrustDID\outlook-plugin\
            ├── manifest.xml        The add-in manifest you point Outlook at
            ├── commands.html / .js Sign / auto-sign-on-send logic
            ├── verify.html         Verification task pane
            ├── settings.html       Add-in settings
            └── assets\             Ribbon icons

These pages are served to Outlook by trustdid-service.exe at https://localhost:8000; the CLI and service themselves live in C:\Program Files\TrustDID\ (see the Software Bundle on Windows guide).

Need help?

Contact support@trustdid.ca with the output of trustdid-service status and your Outlook version (File → Office Account → About Outlook). We respond within one business day for Professional and faster for Business.