Fix Excel Add-in Marked as Untrusted in Trust Center
Question details
The user needs to enable an Excel add-in that supports automated processes but is currently being blocked by security settings.
- Product
- Microsoft Excel
- Device & OS
- not provided
- Scenario
- Running automated processes using a third-party Excel add-in (such as the Federal Reserve Bank of St. Louis add-in) that previously functioned normally.
- Observed behavior
- The Excel add-in is marked as untrusted by the Trust Center, preventing it from executing and breaking automated workflows.
Verify that the add-in comes from a verified and approved source (like an official institution) before modifying your Trust Center settings, as lowering security can expose your system to risks.
Adjust Trust Center Add-in Settings
Use this solution to review and modify your Trust Center settings so that safe, verified add-ins can run without being blocked.
Microsoft Office includes strict security measures that can sometimes flag previously working add-ins as untrusted after an update.
By manually checking the Trusted Add-in Catalogs and Add-ins settings, you can permit specific extensions to run while maintaining overall system security.
Launch Microsoft Excel, click on the 'File' tab in the top-left corner of the ribbon, and select 'Options' from the bottom of the left-hand menu.
In the Excel Options dialog box, click on 'Trust Center' in the left sidebar, and then click the 'Trust Center Settings' button on the right.
Navigate to the 'Add-ins' section within the Trust Center. Check if 'Require Application Add-ins to be signed by Trusted Publisher' is unnecessarily checked. If you are certain of the add-in's safety, adjust this setting.
If the add-in file is saved on your local drive, go to the 'Trusted Locations' section in the Trust Center and add the folder containing the add-in to the trusted list.
Click 'OK' to apply the changes, then close and reopen Excel to ensure the new security configurations take effect.
Check and Update Office Version
Sometimes, outdated Office builds contain bugs that misclassify add-ins. Updating your software can resolve these unexpected Trust Center blocks.
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Frequently Asked Questions
Why did my Excel add-in suddenly become untrusted?
This usually happens when Microsoft Office installs a background security update that changes Trust Center policies, or if the digital signature of the add-in publisher has expired.
How do I add a Trusted Publisher in Excel?
When you open a file containing the add-in, a security warning typically appears in the Message Bar. If the signature is valid, you can click 'Enable Content' and select 'Trust all documents from this publisher' to add them to your Trusted Publishers list.
Is it safe to disable all add-in security checks in the Trust Center?
No. Disabling all security checks makes your computer highly vulnerable to malicious code. It is strongly recommended to only whitelist specific trusted locations or publishers.
