https://dynamicsgpland.blogspot.com/2014/04/windows-application-event-log-fills.html
Upshot:
Copy this text into notepad and save the file as hhctrlfix-64.reg:
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\HHRestrictions]
“MaxAllowedZone”=dword:00000001
“EnableNonInteractiveUser”=dword:00000001
“EnableFrameNavigationInSafeMode”=dword:00000001
With this reg file created, double click on them to import the settings into the registry.