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Solution TitleAcrobat displays a "At least one signature has problems/requires validation" message on files processed by an Enfocus Product.
Solution Number00000446
Solution Details


I have created a CertifiedPDF using an Enfocus product. When I open it in Acrobat, I receive a "At least one signature has problems" message.


Enfocus products automatically add a digital signature when creating a CertifiedPDF document. This signature is a part of the GWG Universal Proof of Preflight standard for embedding preflight information in a PDF file.

This signature is created using a "self-signed certificate." Acrobat doesn't always trust a signature created using a "self-signed certificate" and therefore it displays the "At least one signature has problems" message. Please note, that there is nothing wrong with the content of the file, it can be used without a problem.

The "At Least one signature requires validation" message is triggered when you open a PDF document that uses a signature with a trusted certificate and Acrobat is not setup to validate PDF documents upon opening.


Import an FDF file containing the Enfocus Certificates
  • Please download the FDF file
  • Unzip the file
  • Double click the file to open it in Acrobat
  • Click the “Set contact trust” button
  • Select the first Certificate in the list on the bottom
  • Click the “Trust” button
  • Enable “Use this certificate as a trusted root”
  • Select the second Certificate in the list on the bottom
  • Click the “Trust” button
  • Enable “Use this certificate as a trusted root”
  • Click Import
  • Click Close
Make Adobe Acrobat or Adobe Reader trust the Signature from the PDF
  • Click on the Signature Panel button next to the message
  • Right click on the Signature in the Signature Panel and choose “Show Signature Properties”
  • Click on the “Show Certificate” button
  • Open the Trust tab
  • Click the “Add to Trusted Identities” button
  • Click the OK button on the popup message
  • Click the OK button in the Import Contact Settings panel
  • Click the OK button in the Certificate Viewer panel
  • Click the Validate Signature button

Enfocus created two kinds of Certified PDF files, each having a digital signature, therefore it is possible that this method needs to be performed twice. If you want to avoid this, please use the first method.

If you experience the problem that the error message has now changed to “At least one signature requires validating,” then this can be solved by setting Adobe Acrobat or Adobe Reader to Validate the Signatures upon startup. You can do this using the following steps:

  • Open the Adobe Acrobat or Adobe Reader Preferences on the Security Category
  • Enable “Verify signatures when the document is opened”
  • Click OK
  • From now on Signatures will be verified upon opening the document.

It is possible to setup PitStop Server so it doesn't add the digital signature to PDF files. You can do so like this:

  • Close down PitStop Server including all background processes
  • Download this file and this file
  • Place these files in the following folder:
    Mac: /Library/Preferences/Enfocus Prefs Folder/PitStop Server/
    Win:  C:\ProgramData\Enfocus Prefs Folder\PitStop Server\
  • Start PitStop Server
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