Fix the Acrobat 'At Least One Signature Has Problems' Error in PDF
Question details
The user is unable to sign a PDF document because the software displays an error stating that an existing signature on the document has problems.
- Product
- Adobe Acrobat
- Device & OS
- not provided
- Scenario
- Attempting to add a new signature to a blank signature field in a PDF that already contains one or more existing signatures.
- Observed behavior
- Adobe Acrobat blocks the user from adding a new signature, reporting that 'at least one signature has problems' instead of allowing the document to be signed.
Ensure you are connected to the internet, as your PDF software may need to contact external certificate authorities to validate previous signatures before allowing you to add a new one.
Validate Existing Signatures in Adobe Acrobat
Force Acrobat to verify the existing digital signatures in the document. An unverified prior signature will often block subsequent signing attempts.
Digital signatures rely on a chain of trust. If a document was signed by someone else using a certificate that your computer does not automatically recognize, Acrobat flags it as having 'problems.' Validating the signature or manually trusting the certificate usually resolves this block.
Open your PDF in Adobe Acrobat. Click on the 'Signature Panel' button, which is typically located on the left-hand navigation pane (the fountain pen icon).
In the Signature Panel, look for the option that says 'Validate All' or right-click the specific signature showing a warning icon and select 'Validate Signature'.
If the signature still fails, right-click it and select 'Show Signature Properties'. Click on 'Show Signer's Certificate'.
Navigate to the 'Trust' tab in the certificate window and click 'Add to Trusted Certificates'. Click 'OK', then try validating the signature again.
Flatten the PDF by Printing to PDF
If you do not need strict cryptographic signature tracking and only need to add a visual signature, flattening the document bypasses the error entirely.
Bypass PDF Signing Errors Easily with WPS Office
If Acrobat's strict signature validation continues to block your workflow, consider using WPS Office. It provides a lightweight, highly compatible alternative with a familiar interface, allowing you to view, edit, and sign PDFs seamlessly without getting bogged down by complicated certificate errors. Plus, it offers excellent compatibility with all standard Microsoft Office formats.
- 1. Download and Install: Visit the official WPS Office website and download the free software suite.
- 2. Open Your PDF: Launch WPS Office and open the PDF document that requires your signature.
- 3. Insert Signature: Navigate to the 'PDF Edit' or 'Fill & Sign' tab to easily draw, type, or upload your signature directly into the document.
Frequently Asked Questions
Why does Adobe Acrobat say a signature has problems?
Acrobat displays this error when a previously applied digital signature cannot be verified. This usually happens if the signer's certificate is not in your trusted identities list, if the certificate has expired, or if the document was altered after the signature was applied.
Does an invalid signature mean the PDF is corrupted?
No. An invalid or problematic signature simply means the software cannot independently verify the digital certificate used to sign it. The core content of the PDF is generally safe and fully readable.
How do I clear or remove a problematic signature from a PDF?
If you are the original signer, you can right-click your signature and select 'Clear Signature'. However, you generally cannot clear signatures applied by other people for security reasons. Instead, you may need to ask the sender for an unsigned copy or flatten the document.
Will fixing the signature error change the PDF content?
Validating the signature simply updates the trust settings within your PDF software; it does not alter the actual text or layout of the document. If you choose to flatten the PDF to bypass the error, the content remains the same, but interactive fields become static.
