Adobe Acrobat preview may fail. This happens typically when Actifile and EDR (and other security systems) exceed the Acrobat timeout (which is exceptionally short). For encrypted files it may show the following message: “This file can’t be previewed.”.
When this happens, a good workaround is to switch the previewer from Acrobat to another previewer – for example, the Microsoft PDF previewer.
Microsoft PDF previewer is reliable – and doesn’t have the short timeout that the Adobe Previewer has:
Configure manually:
To switch the previewer you will need to edit the Registry or use a preview handler editor like https://support.actifile.com/wp-content/uploads/2024/04/PreviewHandlerEditor.zip.
You will need to at the very least assign the “.pdf” class to the Microsoft PDF Previewer handle. But we recommend that all pdf classes be associated with the Microsoft handler. See below:
Please note that for the handler to work, the process msedgewebview2 must be set to “always decrypt” in the whitelist. See below:
Configure automatically:
If you prefer to set this up using the RMM (or group policies) you’ll have to edit the registry key associated with the .pdf class root.
Computer\HKEY_CLASSES_ROOT\.pdf\ShellEx\{8895b1c6-b41f-4c1c-a562-0d564250836f}
There may be other keys for thumbnail preview and other viewers – ignore those.
Change the key’s default value from the current value (usually {DC6EFB56-9CFA-464D-8880-44885D7DC193} for Acrobat Viewer) to {3A84F9C2-6164-485C-A7D9-4B27F8AC009E}.
Remember that you will have to ensure that the whitelist value for mswebview2 is set to Always Decrypt and Local.