Unable to attach sql database (Microsoft SQL Server, Error: 5120)

Error Message: While attaching the mdf & ldf file in sql it is showing error

Unable to open the physical file "C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\DATA\C.mdf". Operating system error 5: "5(Access is denied.)". (Microsoft SQL Server, Error: 5120)

Solution: This problem may be occurred due to few reasons Which showing here.

Reason 1: You didn’t open your SSMS through Administrator right

Log off your Computer\Close SQL Management studio.

And Run your SQL Management studio with Administrator 

And try to Attach or Restore it. 

It should work!!

Reason 2: You are not using Window Authentication account

Run SQL Server Management as Administrator

Login SQL Server with Windows Authenticate

Attach your DB Files

Reason 3: Don’t have the permission on folder

GO to the folder where you have stored mdf file.

Select file-> Right click ->click on.

Give full permissions to file for logged in user Security.