How to verify the permissions on a folder (4218365)

AT times a process may fail because the user runnig the process doesn't have adequate permissions.

To verify the permissions for deletion on the folder where the LiteSpeed files are stored.

Please run the following dos command using the SQL Server service account that has problem (then let's try the command with you logged in as yourself, since you're probably a SysAdmin):
dir /B /O-D /TW <full path of a directory that the instance backed up to>

This will determine that the SQL Server can see on the destination directory, it does a list, then the delete.