After I accidentally denied access to everyone, how do I get access back?
A customer went to a folder and used the Security control panel to change its permissions to deny all access to everyone. After applying the changes, they realized that they had denied access to everyone, including themselves. How can they undo their changes and get things back to the way they were?
Congratulations, you locked your keys in the car.
In order to get things back to the way they were, you first need to know how they were before. In general, the system does not keep a history of changes with the ability to undo them. If you delete a file, then it’s gone. If you overwrite a file, the old contents are lost. And if you change the security on a folder, the old security settings have been replaced.
If you’re lucky, you might be able to find a backup that tells you what the security settings used to be for the folder and all of the items in the folder tree, and then you can go to the painstaking effort of reapplying those settings on the original items. I believe the technical term to describe this is “not fun”.
If the folder had default permissions before you accidentally messed them up, you can return to the default permissions by going to the Advanced security property sheet and (1) enabling inheritance, and (2) deleting all non-inherited permissions.
One small consolation is that even though you denied yourself access to the folder, if you are the owner of the folder, you still retain
WRITE_DACL access, so you at least have permission to replace the access control list with a copy from the backup. (And if you aren’t the owner of the folder, you’ll have to go find the owner of the folder and apologize for messing up their folder.)