After Sept/Oct Windows updates, most of the machines in our network are getting the error below. If we fix the NTFS permissions it works again, but the error comes back again after a few hours. It seems to be resetting the permissions of the Appdata folder over and over again.
Outlook Data File Error: File access is denied. You do not have the permission required to access the file: C:\Users\username\AppData\Local\Microsoft\Outlook\username.ost.
We are able to temporarily fix the issue by uninstalling the update, pausing windows update, then fixing the permissions. But the error came back after the update pause expired. VERY FRUSTRATING!
Not sure which update is causing the issue, but I think it is one of these: Security Update for Microsoft Windows (KB3200970) Update for Microsoft Windows (KB5017035)