Unable to create or restore MSSQL database via Plesk GUI:
Unable to restore database 'databasename'
Not valid backup: Cannot open backup device 'C:\Program Files (x86)\Parallels\Plesk\Backup\example.com\databases\databasename\database_name.bak'.
Operating system error 5(Access is denied.). VERIFY DATABASE is terminating abnormally.
MSSQL Server is running under NetworkService account.
NetworkService account account doesn't has all deny permissions on C:\Program Files (x86)\Parallels\Plesk\Backup\ folders.
Switch Log on from NetworkService account to Local system account in Services > SQL Server > right click > properties > Log On