I have connected 2 Ext HDDs(same model) into same machine, one of them is not working after a system reboot. I have tried connecting that into another machine and its detecting as Generic USB hub only.

Ext HDD Model: Iomega® UltraMax 1TB Triple Interface External Hard Drive

Any help you guys can provide would be most helpful.

Are you able to access the drive? If so format it again and plug it into the other machine and see if it recognizes it.

I am not able to access the drive, reason is there are 2 disks in the enclosure and the disks are configured as RAID 0.

I'll refer you to a few different posts (i haven't had a chance to re-structure them yet so they just refer to each other).

1. There have been so many USB bugs in Windows you should simply start with Windows Update. (make sure you have all the hotfixes) and latest service packs See [post=126038]USB Device Problems? Check for Windows Updates[/post]

2. The USB drive you mention should create several entries in Device Manager (one of them being Generic Hub). I'd also expect USB Mass Storage Device and Disk Drive. I'm guessing you'll find Mass Storage Device. But you need check if the Disk Drive item appears or not.

3. See this Guide Troubleshoot: Windows Won't Recognize Your USB Hard Drive. Determine if the drivers are appearing in Device Manager.

4. If yes, look at the Disk Management issues. Otherwise, also See [post=752196]How to Check Hardware / Connection Issues with your USB Device[/post].
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