I’ve joined my computer to a Domain. Therefore I migrated my User Profile (under Computer -> Properties -> Advanced System Settings -> User Profiles). It… let’s say: worked.
But I couldn’t save attachments in Outlook.
Can’t create file: Right-click the folder you want to create the file in, and then click Properties on the shortcut menu to check your permissions for the folder
The problem is, that Outlook saves a path to a “OutlookSecureTempFolder” in the registry. This path pointed to my old profile where my new user has no right to write to. I changed the path to my new profile path, restarted Outlook and it worked.