Have you ever had a Plug N Play or USB device that never worked right after removing it from the computer and plugging it back in, or a suspend/resume?

One of our clients does external USB drives for an offsite backup once per week. This drive wasn’t being automaticly recognized when it was plugged back in, like you’d expect. This meant that someone (Darien in this example) would have to RDP to their server and manually Device Manager rescan for new items. The problem is that if you forget to do this, the target media is unavailable. What to do??

After a quick bit of research, I found a utility to help out Darien in his quest to get rid of this problem. The utility is devcon.exe and is available for free from Microsoft here.The download package contains both 32-bit and 64-bit versions, so be sure you use the propper file. The program is a stand alone .exe and does not require any installation. The KnowledgeBase article says it works with Windows 200, XP, and 2003. No mention is made of Windows Vista, 7, or 2008, so if anyone tries it, please update.

The utility offers the ability to enable, disable, list, and remove devices as well as deleting, listing, and updating their drivers, and other useful information. For this particular problem, I copied the 32-bit version to C: and used:

c:devcon.exe rescan

Notice the lack of / or – before the command argument. I didn’t try it with either as the Help for the utility didn’t show it being used either. It might or might not work with a switch prefix.

This coupled with learning how the pre and post commands work in Backup Exec (thanks Jay V!) may just have squashed this issue. As the client is closed this week for vacation, we won’t know for certain until they resume normal business, but everything looks good!

[Source: Microsoft KB Article 311272]