Backup Exec 2012 hangs on detecting devices

What sort of devices are being used ? And errors in the Event Viewer ?

You may run discover.exe & post/pm the output using this KB - http://www.symantec.com/business/support/index?page=content&id=TECH87501

I ran the discover command - output below:

C:\Program Files\Symantec\Backup Exec>discover.exe

System Page Size: 4096

ByName: Tape
CreateFile on \\.\Tape0 failed, 32 - The process cannot access the file because
it is being used by another process.

ByName: MediumChanger

ByName: Changer

ByPort: Scsi

ByGuid: Tape

  02:00:01:00 01 00 \\?\scsi#sequential&ven_hp&prod_ultrium_5-scsi#5&1982005&0&0
00100#{53f5630b-b6bf-11d0-94f2-00a0c91efb8b}
              INQ 00 "HP      Ultrium 5-SCSI  Z5AD"
              INQ cc ""
              INQ dc ""
              INQ 83 "HP      Ultrium 5-SCSI  HU1225NURR"
              INQ 80 "HU1225NURR"
              TUR 00 00000
              RES 00 34 00000
              REL 00 34 00000
              MAX drive bytes 0x0
              MIN drive bytes 0x0
              BUS SAS(10)
              MAX controller bytes 0xffffff pages 0x101

ByGuid: Changer

ByGuid: ChangerIomega

ByGuid: CDRom

  01:01:00:00 05 00 \\?\ide#cdromnecvmwar_vmware_ide_cdr10_______________1.00___
_#5&290fd3ab&0&1.0.0#{53f56308-b6bf-11d0-94f2-00a0c91efb8b}
              INQ 00 "NECVMWarVMware IDE CDR101.00"
              INQ cc "NECVMWarVMware IDE CDR101.00"
              INQ dc "NECVMWarVMware IDE CDR101.00"
              INQ 80 "?"

Lets cut straight to the chase here.

Post your adamm.log from \program files\symantec\backup exec\logs.

adamm file attached

[4844] 12/07/12 21:28:48.384 DeviceIo Discovery - start
[4212] 12/07/12 21:30:20.790 Adamm Log Stopped!

DeviceIo isn't finishing.

Please list all devices attach to this system.

Systematically disconnect each device from the backup server until the device discovery reports that it has finished.

If you have questions, repost your updated adamm.log for review.