My eID - Digital Signature Shows as "Untrusted" in Adobe Acrobat on New Computers

Issue

When opening a digitally signed PDF on a new computer or a fresh installation of Adobe Acrobat / Acrobat Reader, the signature may display as untrusted or show a warning such as "At least one signature has problems" or "Signature validity is unknown."

This does not mean the signature is invalid. It means Adobe has not yet downloaded its list of trusted certificate issuers.

Cause

Adobe validates digital signatures against trusted certificate lists — the Adobe Approved Trust List (AATL) and the European Union Trusted Lists (EUTL) — which must be downloaded from Adobe's servers.

On a new installation, these lists are not yet present. Adobe only downloads them when it first encounters a signed document, and the download requires the relevant setting to be enabled (it is enabled by default, but should be verified).

The download can also be slow on corporate networks. In testing, computers on the Cayman Islands Government (CIG) network took noticeably longer to download the trusted certificate lists — likely due to network filtering of Adobe's servers — while a computer off the network downloaded them instantly. Users on corporate or slow networks may therefore see the "untrusted" warning for a while before it resolves.

Resolution

Step 1: Verify the trust settings are enabled

1. Open Adobe Acrobat or Acrobat Reader.
2. Go to Edit > Preferences (Windows) or Acrobat > Preferences (Mac).
3. In the Categories list, select Trust Manager.
4. Confirm both of the following options are ticked:
   • Load trusted certificates from an Adobe AATL server (under Automatic Adobe Approved Trust List (AATL) updates)
   • Load trusted certificates from an Adobe EUTL server (under Automatic European Union Trusted Lists (EUTL) updates)

(Insert screenshot of the Trust Manager preferences screen here.)

Step 2: Trigger the download

1. While still in Trust Manager, click Update Now under both the AATL and EUTL sections to force an immediate download of the trusted certificate lists.
2. Alternatively, simply open a digitally signed PDF — this triggers the download automatically.

Step 3: Allow time for the download

• On corporate networks (including the CIG network), the download may take several minutes due to network restrictions. This is normal — leave Adobe open and try reopening the signed document after a short wait.
• Once the lists have downloaded, close and reopen the signed PDF. The signature should now validate correctly.

If the issue persists

• Confirm the computer has internet access and that Adobe is not blocked by a firewall or proxy.
• Try the Update Now buttons again after a few minutes.
• If the signature still shows as untrusted after the trust lists have downloaded, escalate to the helpdesk by emailing eidsupport@egov.ky, as the issue may relate to network filtering of Adobe's certificate servers.

Summary