Fix Untrusted Microsoft Office VBA Signing Certificate Error
Question details
The user is encountering an untrusted certificate error when dealing with digitally signed VBA projects, specifically tied to Subject Interface Packages.
- Product
- Microsoft Office
- Device & OS
- not provided
- Scenario
- Running or verifying digitally signed VBA projects within Microsoft Office.
- Observed behavior
- The VBA signing certificate is flagged as not publicly trusted, lacks a timestamp, and appears to be issued by the Microsoft Testing Root Certificate Authority 2010.
Ensure you have administrator access to your Windows system, as modifying certificate trust settings or policies requires elevated privileges.
Consult Microsoft Server Security Forums
Because this issue involves root certificate authorities and code-signing trust rather than standard Office usage, specialized assistance from security experts is highly recommended.
Certificate chains issued by testing authorities (like the Microsoft Testing Root Certificate Authority 2010) are deliberately isolated from public trust. Resolving this often requires evaluating internal development setups or reporting bugs to Microsoft.
Export or take note of the exact certificate details, including the issuer name, validation period, and the specific error regarding the lack of a timestamp.
Navigate to the official Microsoft Q&A website and locate the Windows Server Security forum.
Submit a detailed question containing your certificate chain and signing status so Microsoft security specialists can evaluate the trust issue and provide a definitive resolution.
Adjust Macro Security Settings in Microsoft Office
If you are in a secure testing environment, you can temporarily adjust Trust Center settings to allow the macro to run despite the certificate warning.
Manually Install the Testing Certificate to Trusted Root Authorities
If you are developing or testing software and trust the source of the Microsoft Testing Root certificate, you can manually install it into your local machine's certificate store.
Switch to WPS Office for a Streamlined Experience
If complex Microsoft Office security policies, macro restrictions, and untrusted VBA certificate errors are disrupting your workflow, consider using WPS Office. It provides a lightweight, highly compatible alternative that handles daily document, spreadsheet, and presentation needs without the steep troubleshooting curve.
Frequently Asked Questions
Why is my Microsoft Office VBA certificate showing as issued by a Testing Root CA?
This usually happens in development or beta environments where preview builds of Office or specific subject interface packages are signed using internal Microsoft testing certificates rather than publicly trusted root certificates.
Can I ignore the untrusted VBA certificate warning in Microsoft Office?
While you can bypass the warning by modifying your Trust Center settings, it is highly discouraged for production environments. Ignoring trust warnings can expose your computer to potentially malicious and unauthorized scripts.
How do I fix a missing timestamp on a digital signature?
A missing timestamp means the signature wasn't verified by a Time Stamping Authority (TSA) when it was applied. To fix this permanently, the original developer must re-sign the VBA project and include a valid timestamp server URL during the code-signing process.
Where can I get specialized help for Windows Server Security certificate issues?
The most effective place to resolve advanced certificate and code-signing trust issues is the Microsoft Q&A forums, specifically under the Windows Server Security tag, where security experts can directly analyze your certificate chain.
