Originally Posted by Resiak
Your error message sounds as if your database is corrupted. Hope you have backed up your data elsewhere so you can copy it back to the Cowon. You should try to do a database update first. You can find this option by going into "system" and you will find it on the 3rd page. You must also set USB mode to "MSC" and not MTP. This too is on "System" on page 2. The firmware upgrade has to be copied to the flash drive of the Cowon and not the Hard drive. You may have done all this, but if you haven't, try these first. If this fails to solve your problem, you may have to format the hard disk.
Normally before I try to format the HD, I'd connect in MSC mode and run your favorite CHKDSK software. Which can possibly fix a corrupted db saving you from formatting the HD and losing all your data. Naturally if that doesn't work I format and re-firmware as you've suggested. Regardless always having a back up of your data for restoration is critical, again as you stated.