One of the annoying issues in SharePoint is working with DB problems;
one of these problems is restoring content DB, to solve this problem follow the below steps:
- First you should take backup normally the way you want
- If accidently crash happened in DB, try to restore the content DB the normal way
- You will not be abled because there is error (can’t restore database because it’s in use)
- My simple solution is to take this DB Offline first from both SharePoint Central Administration, and from SQL Server, then make your normal restoration.