SQL SERVER – FIX : Error 945 Database cannot be opened due to inaccessible files or insufficient memory or disk space. See the SQL Server error log for details
This error is very common and many times, I have seen affect of this error as Suspected Database, Database Operation Ceased, Database Stopped transactions. Solution to this error is simple but very important.
1) If possible add more hard drive space either by removing of unnecessary files from hard drive or add new hard drive with larger size.
2) Check if the database is set to Autogrow on.
3) Check if the account which is trying to access the database has enough permission to perform operation.
4) Make sure that .mdf and .ldf file are not marked as read only on operating system file system level.
Reference : Pinal Dave (https://blog.sqlauthority.com)