Question No bootable device error when external HD with 2 partitions is connected

Jul 11, 2019
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I just bought a 10GB WD My Book external backup drive, and partitioned it because FileHistory doesn't allow you to cap the amount of space it takes over, and I wanted to use half of the drive for personal files. Everything runs fine until I create the second partition in Windows Disk Management, which creates automatically as a "Simple Volume," Primary Partition and assigns a drive letter. The next restart, the computer will not boot up, says no device found, and ignores the BIOS (UEFI) order of startup. It will not boot to the bootable USB thumb drive in this state either. The BIOS boot order is set to look at the hard drive windows system first. I can only get Windows to boot once I unplug the new external HD. Once logged in, I can plug the drive back in and see my drives and files, but any new restart requires unplugging the drive.

I've wiped the computer clean, reinstalled Windows 10 from scratch, deleted the second partition and recreated, always same result. If I leave the first partition alone and leave the remaining space as unallocated, things start up fine. I've tried DOS commands "bootrec /fixboot, fixmbr, rebuildbcd", etc. with no change or fix (get an "access denied" error when trying "fixboot" but all others ran successfully without fixing anything). BIOS does not have a "Legacy USB" setting, and if I turn off USB in general, then the drive (and all other USB devices) are useless after booting up.

Bottom line is that when the external drive has more than 1 partition, the system will only allow booting from that drive when it's plugged in. Other boot options are only available if the drive is unplugged.

Any thoughts on anything else I can try? I'm pretty frustrated. Many thanks!
 

onespeedbiker

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Apr 13, 2019
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Advise make and model of PC, motherboard, make, model and size of drives you are using. Did you partition the "My Book external backup drive" (I assume it's 10tb not gb) , with GPT or mbr? What about your other drive(s). Could you post a screen shot of your disk manager? As a stab in the dark, I would say that when a second partition is added to your external drive, windows sees it as a boot drive. Is the primary partition on the external drive active? For some reason when using File History (I use a USB), the primary partition is often made active, meaning my PC was constantly trying to boot off the File History USB until I changed the partition to inactive; I needed a third party utility to do so, because Windows Disk Manager won't delete a primary active partition.
 
Jul 11, 2019
4
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Dell XPS 8700
400-AADU : 2TB 7200 rpm Hard Drive + 32GB mSATA Solid State Drive
Baseboard OKWVT8 - A03

Yes, 10TB, sorry for the typo. It's a Western Digital MyBook.
I created the partitions in Windows Disk Management (just right-clicked, New Simple Volume, kept all defaults). Not sure if it uses GPT or mbr.

I can't tell if the new partitions are Active (there doesn't seem to be an attribute anywhere stating one way or another in Disk Management). When I right-click on both partitions, the Mark Partition as Active selection is greyed out though.

What 3rd party sw did you use to make the partition inactive? I've been looking in Disk Mgmt and can't find a way there either.

I've linked a screen shot of my disk setup. I've got the 2nd partition on the WD external deleted and the space unallocated right now, so that I can restart the PC without unplugging the darned thing each time.

https://photos.app.goo.gl/YBgrA9YQtBHdpcbN8

Thanks for your help!
 
Jul 11, 2019
4
0
10
0
Dell XPS 8700
400-AADU : 2TB 7200 rpm Hard Drive + 32GB mSATA Solid State Drive
Baseboard OKWVT8 - A03

Yes, 10TB, sorry for the typo. It's a Western Digital MyBook.
I created the partitions in Windows Disk Management (just right-clicked, New Simple Volume, kept all defaults). Not sure if it uses GPT or mbr.

I can't tell if the new partitions are Active (there doesn't seem to be an attribute anywhere stating one way or another in Disk Management). When I right-click on both partitions, the Mark Partition as Active selection is greyed out though.

What 3rd party sw did you use to make the partition inactive? I've been looking in Disk Mgmt and can't find a way there either.

I've attached a screen shot. I've got the 2nd partition on the WD external deleted and the space unallocated right now, so that I can restart the PC without unplugging the darned thing each time.

Thanks for your help!
Advise make and model of PC, motherboard, make, model and size of drives you are using. Did you partition the "My Book external backup drive" (I assume it's 10tb not gb) , with GPT or mbr? What about your other drive(s). Could you post a screen shot of your disk manager? As a stab in the dark, I would say that when a second partition is added to your external drive, windows sees it as a boot drive. Is the primary partition on the external drive active? For some reason when using File History (I use a USB), the primary partition is often made active, meaning my PC was constantly trying to boot off the File History USB until I changed the partition to inactive; I needed a third party utility to do so, because Windows Disk Manager won't delete a primary active partition.
PS- did some more research and all of my partitions are gpt, meaning "Active" doesn't mean anything, apparently (it's only significant with mbr drives). From what I've read, I need to use bootrec commands, but keep getting "access denied" when I try.
 

onespeedbiker

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Apr 13, 2019
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It appears you are booting from your 2TB hard drive, I also see your 10tb hardrive (with one partition, but I do not see a 32bg ssd. Also, there is noting bootrec will do that will make any difference to your issue. As far as your Western Digital MyBook not allow windows 10 to boot with two partitions, I would look at these fixes; I would start by loading the driver WD has for it's MyBook drives, to stop this very thing. https://helpdeskgeek.com/help-desk/unable-to-boot-windows-with-external-hard-drive-attached/ Further, if you must use bootrec, here are some fixes for that also, https://www.partitionwizard.com/clone-disk/bootrec-fixboot-access-is-denied.html. I have used easeUS Partition Master, to delete GBT partitions.
 
Reactions: MikeMDenver
Jul 11, 2019
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Well, I’m up and running, although not entirely sure how. I first tried to install the Western Digital Windows SES drivers, per the first link you sent, and while the install seemed to go with no errors, it installed nothing (did not even create the directory c:\Windows\Western Digital that was referenced during the install). Other folks online had same issue and it someone said that WD is now only using the Windows drivers (although why provide a driver install that does nothing). Anyway… moving on…

Decided to try to repair the UEFI boot order, but had run into access denied issues earlier. Followed these instructions below. Not sure which part of this is what did the trick, but at this point, Windows starts up even with the external drive connected (with 2 partitions), although it takes an extra moment to flash a dos screen before starting up now.

First, I had to track down an old iso for windows (ver 1703). The current version has an issue for some users when you use it to boot to USB it gives an “access denied” error when running bootrec /fixboot command. I created the new recovery USB stick with that older iso and then followed these steps:

Created the 2 partitions in disk management on the WD external HD (both show as primary and are assigned drive letters).
Unplugged the WD HD (otherwise, no restart possible).
Using the new USB stick, booted to recovery options, selected Repair Computer / Advanced / Command Prompt.
DISPART
sel disk 0
list vol
sel vol 4 (the EFI partition on C with the boot info)
assign letter=T:
exit
T:
format T: /FS:FAT32
bcdboot C:\windows /s T: /f UEFI
cd T:
bootrec /fixboot
bootrec /rebuildbcd
exit
I restarted and still errored out on boot.

Went to BIOS boot options and set SECUREBOOT option to Disabled. Restarted, and now all works. Again, not sure if the bootrec commands did anything at all; it may have just been turning off the SECUREBOOT option that did the trick. Can't remember if I had tried that earlier or not. In any case, unless I find that the changes I made did some terrible damage to something down the line, I think I'm good now.

Thanks again for taking the time to give me some advice!
 

onespeedbiker

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Apr 13, 2019
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Windows 10 Secure boot is a very rigid protocol that will not allow booting if some part of the booting protocol is not identified as Desined for Windows 10; this can often be software and/or firmware updates, or some UEFI compatibility issue. The more you bring to the table, the greater the probability Secure boot will cause you problems. If you PC works with secure boot, than you are likely not going to be infested with a root kit, but otherwise it's more of a mandate what you can use with Windows 10 and what is not allowed.
 

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