My workstation is using NTFS, Outlook 2007 with Exchange 2007 server.
My outlook.ost file is 1.7GB.
As my Outlook runs into problem, I tried to copy the outlook.ost file to another location for repair, but I keep getting CRC errors and the file was not copied.
I also tried to use winrar to compress it and it runs into the same CRC error.
Q#1. What causes this CRC error? hard disk error or software?
Q#2. How to repair such CRC error?
Thanks.

Hi Peter,

The cyclic redundancy check, or CRC error, indicates a bad spot/corruptions within the file that you are trying to copy and in lot of cases with your hard disk.

To make sure if the problem is with the .ost file or your hard disk, you can fire up a Command Prompt window, and then copy the file to NUL:

C:>CD (path of your .ost file)
C:(path of your .ost file)>copy name.ost NUL

If this succeeds, the problem is with your .ost file. If this fails, it should be a hardware based disk issues.

If it's an issue with your .ost file, I'd suggest to run scanpst.exe tool to repair your data file, then check if this fixed it.

When the issue is hardware based, you probably need to find Disk Errors in the System log of your Event Viewer. You can access the Event Viewer by going to: Control Panel-> Administrative Tools-> Event Viewer

By the way, .ost file is actually a local copy of your mail items on the server. For a corrupted .ost file, you actually don't need to "copy the outlook.ost file to another location for repair". You can simply rename it to .ost.old or delete it, and then re-launch Outlook to let it generate a new .ost file from server.

Regards,

Ethan Hua
TechNet Community Support

Have you run a chkdsk on this drive lately?

Try running this command:
chkdsk /f <drive letter>:

Or:

OST Repair Kit is a compact Outlook OST repair tool download intended for all Outlook users who want to how to repair OST files on their own.

For more information: http://www.ost.repair/

Also look here: http://www.filerepairforum.com/forum/microsoft/microsoft-aa/outlook/1351-how-to-open-outlook-ost-file

• Marked as answer by PeterCurt 17 hours 43 minutes ago