Adobe Acrobat & Adobe Sign Signature Diagnostics
Adobe Acrobat surfaces signature problems as terse 'validity unknown' or 'invalid' banners. We map those banners back to the actual PKI failure — trust list, revocation reach, timestamp, or signature handler — and produce a written remediation plan.
Symptoms we triage
- Signature validity is UNKNOWN in Acrobat Reader
- At least one signature has problems
- AATL trust list missing or stale
- Adobe Sign envelope shows 'certificate not trusted'
- Timestamp server error during PDF sign
Diagnostic flow
1. Run Acrobat preference audit
Expected: AATL + EUTL enabled, custom trust reviewed
2. Refresh AATL
Expected: Latest trust list timestamp within 30 days
3. Re-validate signature with revocation checking
Expected: OCSP / CRL fetch succeeds
OS coverage
Windows 10 / 11
- • Acrobat trust preferences
- • Windows CAPI handoff
- • Edge PDF viewer fallbacks
macOS Sonoma / Sequoia
- • Acrobat on macOS Sonoma / Sequoia
- • Preview.app signature limitations
- • Keychain identity selection
Adobe Acrobat troubleshooting library
In-depth diagnostic write-ups for each common Adobe Acrobat failure mode.
Frequently asked
Are you Adobe support?
No. We are an independent consultancy specialising in PKI and digital signatures. We are not affiliated with Adobe Inc.
Will you modify the original PDF?
No. Diagnostics never alter the source document; remediation is documented for your team to apply.
Related fix guides
Step-by-step diagnostic write-ups for the most common Adobe Acrobat errors.
Ready for a structured Adobe Acrobat diagnostic?
Independent consulting, screen-shared Zoom session, written remediation summary.