Broken NTFS Permissions for MSSQL$SQLEXPRESS I have been &quot;securing&quot; our database server. To do this I removed some permissions from the folders that the SQL Express install created.
D:\SQL
D:\SQL\Data
D:\SQL\Backup
etc..

I kept the permissions on the Data folder as they were, but I removed anything I thought I didn't need from the others.
Now I can't backup databases. If I try selecting the backup location the dialog doesn't show anything in the d:\SQL folder and if I put the path in myself it tells me this:-

Cannot access the specified path or file on the server. Verify that you have the necessary security privilages and that the path and file exists.
...

It looks like folder permission problem. Another server configured in a similar way has a bunch of &quot;allow&quot; permissions for an account called &quot;MSSQL$SQLEXPRESS&quot;, (which I know I deleted), But I can't re-add these permissions because there is no such group, user or built-in security principle on the server.
How do I add permissions for this MSSQL$SQLEXPRESS account?
This account is a service SID.

The full name is NT SERVICE\MSSQL$SQLEXPRESS.