Acrobat Freezes or Crashes During Digital Signatures Issue: Acrobat may freeze or crash when attempting to apply digital signatures to a document, particularly when Protected Mode or Enhanced Security is enabled. Workaround: Disable Protected Mode in Preferences > Security (Enhanced). Check that the digital certificate being used is valid and up-to-date. Corrupt or expired certificates can cause signing to fail. Use an alternative signature format, such as a signature image, if the problem persists.