The latest release of ENS 10.6.1 (July release) prevents Adobe reader from starting in Protected mode and also prevent Outlook from viewing pdf's in preview mode
A suggest workaround (from McAfee) was Disable Exploit Prevention, or set Adobe to not run in protected mode. Both of these workarounds are removing security.
A better way around is to Exclude **\AcroRd32.exe in the Application Protection Rules section of Exploit Prevention.
Is there going to be a hotfix for this? I have tested with the may update and this issue doesn't happen, so it's definitely being caused by the July update.
Fortunately, I haven't pushed the July version out to many machines, but the Win 10 1903 machines that didn't have McAfee (about 200 of them) are now getting a separate Exploit Prevention policy to allow pdf's to be read.
This appears to be a replica of the problem with VSE 8.7 from about 9 years ago!
Solved! Go to Solution.