How to fix "System.Data.SqlClient.SqlError: Read on "C:\Data_2012.mdf" failed: 23(Data error (cyclic redundancy check).) (Microsoft.SqlServer.Smo)"

Question

How to fix "System.Data.SqlClient.SqlError: Read on "C:\Data_2012.mdf" failed: 23(Data error (cyclic redundancy check).) (Microsoft.SqlServer.Smo)"

Nhlanhla Makhubo 0

Greetings,

Please assist with fixing an error encountered when trying to restore a database on MS SQL 2012.
Error reads: "System.Data.SqlClient.SqlError: Read on "C:\Data_2012.mdf" failed: 23(Data error (cyclic redundancy check).) (Microsoft.SqlServer.Smo)

Viorel 126.9K Reputation points

2025-08-18T09:29:36.68+00:00

Probably the file or hardware is corrupted. (It is not a problem of SQL Server on this stage). Do you have another, good copy of this file?

The drive and files should be checked using the Check Disk tool from the Properties dialog for C: in File Explorer, or using the chkdsk command-line utility: https://www.bing.com/search?q=windows+check+disk.
Erland Sommarskog 134.4K Reputation points MVP Volunteer Moderator

2025-08-18T21:31:01.0233333+00:00
That does not look good. Either the backup is damaged, or the place you are writing has hardware problems. Let's hope for the latter. I also like to point out that the location for the database file is not the best one.

To get as much error information as possible, don't use the UI, but use T-SQL. You can set up the BACKUP command in the UI, but use the script button on top to get the command in a query window. Make sure that you have sensible location for the files. You would only restore the database to the C: drive, if you are restoring it on your personal computer, not on a server (which typically has dedicated drives for data and log files).

Also, before running the actual restore, run this command

RESTORE VERIFYONLY FROM DISK = '<backuplocation>'

This can give an indication on whether the backup is damaged or not.
Nhlanhla Makhubo 0 Reputation points

2025-08-19T09:10:03.2933333+00:00

Thanks for the comment @Erland Sommarskog . Please note I am attempting to restore the backup on a server, however, the copy restores successfully on my laptop without any issues. This gives me the idea that the issue is with the Server's drive itself. I even attempted to create a new backup from the server and I get the same error.
Erland Sommarskog 134.4K Reputation points MVP Volunteer Moderator

2025-08-19T18:40:08.53+00:00

Please note I am attempting to restore the backup on a server, however, the copy restores successfully on my laptop without any issues.

I can't refrain from asking: Why did you not mention that initially?

Anyway, it certainly suggest that there is an issue with the C: drive on the server. The path you have is terribly wrong - you should never put a database file on the top folder of the C: drive. (And no other drive for that matter.) But even if you do, it should result in CRC errors if the server and drive is healthy.

I assume this is a virtual machine? In that case you should discuss the matter with your VM administrator, as it could be an issue with the virtualisation software.
Nhlanhla Makhubo 0 Reputation points

2025-08-19T18:56:19.39+00:00

Thanks for your help, I shall escalate this to the Server Administrator :)