Windows 10: Boot hangs with usb HDD connected

I have a toshiba 3Tb usb hdd for backup.

Like the title says the boot hangs if it's attached.

I just changed machine and reinstalled windows, and it still happens. It hangs just after the blue Windows appear.

It is marked INactive.
The boot order in the bios is SSD first (usb 2nd)
I can't see any sign of any system on the drive and I can't think I ever installed one

(older forumites might remember I posted the same query on sevenforums which never got resolved. This is a replacement PC of the same general type (dell T3400), but but with win 10 v1909 installed (somewhat to my regret esp WTF have they done with local networking but that's not why I'm here)
Any ideas please

:)

 

Boot hangs with usb HDD connected

Thanks for the quick reply. screenshot below

I don't know mbr/gpt, how can I tell?
It is only used for data backup
and yes have swapped usb sockets

 

Boot hangs with usb HDD connected

Can you post a pic of the disk management of this drive?
Is the external mbr or gpt partitioned?
Have you relocated any programs or folders to this drive?
Have you tried the drive in any other ports?

such as

 

Boot hangs with usb HDD connected

I have a toshiba 3Tb usb hdd for backup.

Like the title says the boot hangs if it's attached.

I just changed machine and reinstalled windows, and it still happens. It hangs just after the blue Windows appear.

It is marked INactive.
The boot order in the bios is SSD first (usb 2nd)
I can't see any sign of any system on the drive and I can't think I ever installed one

(older forumites might remember I posted the same query on sevenforums which never got resolved. This is a replacement PC of the same general type (dell T3400), but but with win 10 v1909 installed (somewhat to my regret esp WTF have they done with local networking but that's not why I'm here)
Any ideas please