PC won't boot while external HDD plugged in

[Mk56TClaire]

My PC:
- Windows 10 1803
- ASRock A320M HDV
- Ryzen 3 2200G
- 2x4GB DDR4 Apacer Panther
- 1TB HDD 7200rpm
- RX 480 8GB Reference
- Seasonic Focus+ Gold SSR-550FX

Hi,
I always leave the external HDD (Samsung M2 Portable 500GB) attached after turn off the PC. And when I turn it off again later with the external HDD still attached, it will boot with no problem. Yesterday when I pressed the power button, the screen is black, Can't get into UEFI because not even motherboard logo showed up. After I turned it off and unplug the external HDD it booted into Windows.

I have this problem too in my old PC (Windows 7) with the same external HDD, after long time I used it with external HDD attached, one day the PC just won't boot unless I unplug it. The difference is while it showed up the motherboard logo and I can get in the BIOS, it showed the "BOOTMGR is missing press Ctrl+Alt+Del to continue" if I continue. Even with a 1GB USB flashdisk plugged it shows that message.
PC can boot if I unplugged any kind of USB storage from the PC.
The CPU and GPU fans are working and I can hear the HDD is spinning although it won't boot (in both PC).

I always unplug the power cable before going to work. Does this can affect?
Should I always turn the PC on without any kind of removable storage attached?
Currently I only need a solution for my new PC, the old one is now used by my parents and they have no problem with it since they never leave any kind of removable storages attached after turn it off.
Any help would be greatly appreciated. Thanks

 

[asoroka]

Have you checked the BIOS boot order, has it changed.

If your primary boot device is selected by BIOS and has a valid boot image, then an external device should not make a difference.

Do you have your BIOS set to wait for F1 on error? It could be that this external drive is starting to fail.

 

[The Paladin]

change bios boot order to start cd-hdd-usb

 

[Mk56TClaire]

Have you checked the BIOS boot order, has it changed.

If your primary boot device is selected by BIOS and has a valid boot image, then an external device should not make a difference.

Do you have your BIOS set to wait for F1 on error? It could be that this external drive is starting to fail.

I've managed to enter BIOS once using ASRock Restart to UEFI utility (I turned it on without the external HDD pluged in, and restart while it's still attached). The boot order are: UEFI 1st, internal HDD 2nd, and if external drive plugged in it's in third order.
I don't know "wait for F1 if error" setting, the screen normally shows this (screenshot from youtube, similar motherboard):

If the external drive plugged in and turn it on as usual, the screen just black and I can't use F2, Del, F11 etc.

The external drive is working perfectly, I still can access my files. Probably PC won't boot too with any kind of removable storage attached, even a new one (not tested in my new PC, but it's an issue in my old PC).