I work for a company who supports many clients with quite a few now having a SBS 2008 server. All of them have a very simliar setup, we are using the built in Backup utility and USB Hard Drives. Most of the clients have 5 usb backup drives that are changed daily monday to friday.
We are having a intermittent problem with a number of clients when drives are changed and the backup that night fails saying it cannot find the destination, We then check My Computer and the drive does not show up (which it shouldnt), have a look in disk management and the drive does not show up, however it does show up in Device Manager. The light is on the drive to show its powered and ive tried unplugging and plugging back in several times with no change i tried plugging in another drive and that shows fine in disk management, plug the other one back in and again not showing up in disk management, if i reboot the server it then appears in disk management and the backup works fine. It will then start randomly happening again sometimes with the same drive sometimes with another drive. As i stated before this is happening with a number of clients who all use USB Hard drives however they are using different makes and sizes of drives. The backups will work fine for a time then suddenly this issue will start happening , reboot the server and its fine for a bit then it starts happening again sometimes after a week sometimes months, i have trailed through lots fo different forums trying to find a solution without much luck, this is a particular article i have recently looked at and again after the server is rebooted it was working fine however the problem comes back again.
This must be a problem others have come across as we are getting it with quite a few clients, it cant be a drive issue as its happening with lots of different drives and they are fine once the server is rebooted, its not down to a particular make or model of drive as different clients are using different drives.
If you need any more detail let me know.