Database back up failed with the below message prompt stating you have no permission to access the DATA folder. On the prompt itself it will show the location/path to the DATA folder.
If Backup Database unsuccessful, below error will prompt:
Grant the read permission access right.
Please try to access the data folder in windows explorer e.g. C:\Program Files\Microsoft SQL Server\MSSQL10_50.QNEBSS\MSSQL\DATA, system may prompt you to grant the access right to this folder.
The prompt also states that you'll get permanent access to the folder by clicking Continue.