Cannot open backup device ‘C:\\Program Files (x86)\\Parallels\\Plesk\\Backup\\yourdomainname.com\\databases\\yourdomainname-182\\123’. Operating system error 5(Access is denied.).
BACKUP DATABASE is terminating abnormally.

Plesk Error:- Unable to take backup of MSSQL database: Operating system error 5(Access is denied)

Did you ever come across this error when you try to generate backup of  domain from backup manger in windows based plesk panel.

Reason:-  

Insufficient permissions on the %plesk_dir%\\Backup\\ folder for the SQL service user.

Resolution:-

–  You need to assign NT Service permission for Account=”MSSQL$SQLEXPRESS” to plesk/backup and private tmp folder.

–  If it will not resolve this issue so you can try another method

Open Service section
Locate and open the SQL Server (SQLExpress)
Go to the LogOn Tab
Choose Local System Account
Click OK  and Restart SQL  service.

Hope it will be resolved this issue. Don’t forget to drop your feedback in comment section.