“At least one signature has problems” Error in Adobe Reader

Digital signatures can be used to protect and validate pdf documents shared by multiple parties

by Vlad Turiceanu
Vlad Turiceanu
Vlad Turiceanu
Passionate about technology, Windows, and everything that has a power button, he spent most of his time developing new skills and learning more about the tech world. Coming... read more
Reviewed by Alex Serban
Alex Serban
Alex Serban
Windows Server & Networking Expert
After moving away from the corporate work-style, Alex has found rewards in a lifestyle of constant analysis, team coordination and pestering his colleagues. Holding an MCSA Windows Server... read more
Affiliate Disclosure
  •  It's perfectly normal for a PDF reader to check for un-validated signatures in a document. The guide below will help you verify signatures on a PDF document.
  • Adobe's software has its fair share of issues; scan through our Adobe How-To Fix guides to learn how to resolve future problems.
  • If you're worried about documents and Windows file security, learn how to protect your computer by reading through our Security & Privacy Software Hub.

‘At least one signature has problems’ – You may have encountered this error while trying to open a signed document on Adobe Acrobat Reader.

It’s even more common if you’re trying to open and read documents digitally signed through electronic signature software and services like DocuSign.

But what does this error actually mean and what can you do to fix it? In the following guide, we’ll explore what causes signature problems in Adobe Acrobat Reader and how you can fix them.

How do I get rid of “At least one signature is invalid”?

Adobe at least one signature has problems


Since Adobe Acrobat Reader does not come with trusted identity data out of the box, it has to download it.

This error arises because the authentication data to validate the signature on the document isn’t available on your system.

In layman terms, Adobe cannot automatically verify signatures that were made using a self-generated certificate through third-party applications such as DocuSign.

These types of certificates are known as self-signed certificates.

However, this warning or error message (“At least one signature has problems”) does not indicate that the signatures on the document are corrupt or invalid. It simply informs the user that the certificates connected to the signatures may not be trusted by Adobe.

The latest version of Adobe Acrobat Reader tries to download the certificate data automatically upon opening a document with digital signatures. An error may occur that disrupts the process.

The easiest way to fix this is by manually validating the certificates and signatures.

Remove at least one signature has problems

  1. Near the end of the ‘At least one signature has problems’ error bar, click on the button labeled ‘Signature Panel‘.
  2. On the panel that displays itself on the left side of your screen, right-click on the signature you want to validate.
  3. Click on Validate Signature.
  4. On the Signature Validation Status dialog click on the button labeled Signature Properties…
  5. On the Signature Properties screen, click on the Show Signer’s Certificate button.
  6. In the Certificate Viewer, click on the Trust tab in the main panel. It should be adjacent to the Revocation tab.
  7. Click on the button marked Add to Trusted Certificates.
  8. Acrobat will display a warning message. Click on OK. 
  9. You can leave the next screen as is and click on OK. 

Alternatively, you can click on the Validate All button. This may be an issue for larger documents with multiple signatures.

If you’re just viewing a document, verifying the certificates attached to a signature is unnecessary.

It’s also important to only manually verify certificates that you trust. Verifying the wrong certificates can pose a security threat.

Nevertheless, this issue isn’t unique to Adobe Acrobat Reader. A lot of other PDF readers suffer from the same issues but they can be handled almost as easily.

You can actually use this as a test to see how secure a PDF reader is.

If it doesn’t scan for untrusted certificates, then it’s not very secure. So it’s less an issue and more a security feature.

Did the solutions in this guide work for you? Do not hesitate to leave a comment down below.

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