I have a Seagate FreeAgent Go external USB hard drive that was mounted but mysteriously decided to reconnect itself:

Sep 30 15:07:06 feinman kernel: [243901.551604] usb 1-1.2: USB disconnect, device number 3
Sep 30 15:07:06 feinman kernel: [243901.553828] sd 6:0:0:0: [sdb] Synchronizing SCSI cache
Sep 30 15:07:06 feinman kernel: [243901.553893] sd 6:0:0:0: [sdb]  Result: hostbyte=DID_NO_CONNECT driverbyte=DRIVER_OK
Sep 30 15:07:10 feinman kernel: [243905.336557] usb 1-1.2: new high-speed USB device number 4 using ehci_hcd
Sep 30 15:07:10 feinman kernel: [243905.431219] scsi7 : usb-storage 1-1.2:1.0
Sep 30 15:07:11 feinman kernel: [243906.427207] scsi 7:0:0:0: Direct-Access     Seagate  FreeAgent Go     0148 PQ: 0 ANSI: 4
Sep 30 15:07:11 feinman kernel: [243906.428303] sd 7:0:0:0: Attached scsi generic sg1 type 0
Sep 30 15:07:11 feinman kernel: [243906.430317] sd 7:0:0:0: [sdc] 625142447 512-byte logical blocks: (320 GB/298 GiB)
Sep 30 15:07:11 feinman kernel: [243906.430860] sd 7:0:0:0: [sdc] Write Protect is off
Sep 30 15:07:11 feinman kernel: [243906.430865] sd 7:0:0:0: [sdc] Mode Sense: 1c 00 00 00
Sep 30 15:07:11 feinman kernel: [243906.431386] sd 7:0:0:0: [sdc] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Sep 30 15:07:11 feinman kernel: [243906.493674]  sdc: sdc1
Sep 30 15:07:11 feinman kernel: [243906.496109] sd 7:0:0:0: [sdc] Attached SCSI disk

It changed from sdb to sdc, causing a number of problems for me. What can I do to further track down the cause?

I thought it might be a problem with it sleeping but when I cat /sys/class/scsi_disk/6\:0\:0\:0/allow_restart, I see that it's already 1.