PDF Security & Access Issues

Fix Cannot Add a Countersignature to a Digitally Signed PDF

Huma Ashraf Ch Oct 23, 2026 868 views

Question details

The user is unable to add a stored signature to an existing, validated PDF because the next signature field is highlighted but unresponsive.

How to Fix Issues Adding a Countersignature to a Digitally Signed PDF

Product: PDF Editor
Device & OS: not provided
Scenario: Attempting to add a countersignature to a document that has already been signed and validated by a previous party.
Observed behavior: The PDF contains a validated signature, but the next signature field cannot be completed with the user's stored signature, likely due to document locking restrictions.

Before you start

Ensure you have the contact information of the original sender, as resolving this issue often requires them to adjust the initial signature permissions and resend the file.

Solution 1Recommended

Review the Existing Signature Properties

Check if the original signer locked the document or applied a certification signature that restricts further modifications.

When a PDF is signed, the signer can choose to lock the document to prevent any subsequent tampering. If this option was selected, no additional signatures can be added without invalidating the document.

Open the PDF document

Launch your PDF reader and open the document containing the validated signature.

Access signature properties

Right-click on the existing digital signature in the document and select 'Signature Properties' or 'Show Signature Properties' from the context menu.

Check document restrictions

Review the 'Document Restrictions Summary' or 'Permitted Changes' section to see if filling in forms or adding further signatures is allowed.

Review the Existing Signature Properties

Signature Certifications: A 'Certification Signature' is often stricter than an 'Approval Signature' and can permanently lock all fields to guarantee document integrity.

Solution 2

Request a Correctly Configured Copy

If the document is locked by the previous signature, the sender must modify their signature settings before sending it to you.

Advanced PDF Features

Manage Digital Signatures Seamlessly with WPS Office

WPS Office provides a highly compatible, robust PDF Editor that makes adding, verifying, and managing multiple digital signatures straightforward and secure.

1. Open your PDF: Launch WPS Office and open the PDF document that requires digital signatures.
2. Navigate to the Protect tab: Click on the 'Protect' tab in the top ribbon and select 'Sign Document'.
3. Create or import signature: Add your digital ID or stored signature. If you want others to sign after you, ensure 'Lock Document After Signing' is left unchecked.
4. Save and share: Apply the signature, save the file, and securely share it with the next recipient for their countersignature.

Easily set document permissions and locking featuresSupports multiple digital signatures on a single documentFully compatible with standard Microsoft Office and Adobe PDF formatsLightweight, free, and intuitive user interface

microsoft office alternative - wps office

Frequently Asked Questions

Why does a PDF become completely locked after one person signs it?

This happens when the signer selects a setting (such as 'Lock Document After Signing' or applies a 'Certifying Signature') to ensure no further changes, including additional signatures, can be made. This guarantees the document's absolute integrity.

Can I unlock the signed PDF to add my signature?

No, forcefully unlocking or modifying a signed PDF will instantly invalidate the existing digital signatures and break the document's chain of trust. You must request a copy that was not locked upon the initial signing.

How can a sender prepare a document for multiple signatures?

The sender should add multiple signature fields before anyone signs. When applying the first signature, they must ensure any options that restrict further filling or lock the document are disabled.

PDF Troubleshooting