bitlocker – Why can’t I type reliably at my pre-boot password prompt?

When using either Veracrypt or BitLocker full system disk encryption for my Windows 10 pro install I see the behavior seen in this gif.

animated gif showing an empty veracrypt preboot password prompt, me hitting a single key, and then an inordinate number of characters showing up on screen

A single key press at the boot authentication screen results in multiple characters being added to the password field. It seems like the input is distorted somehow so that multiple characters are entered. It’s as if the keyboard is too sensitive/fast.

If I hit “Esc” or otherwise try to drop down to the preboot recovery tools the screen shows a progress bar then freezes. The screen locks up at different points in the progress bar when that happens. It’s not consistent. 1/50 or so times I’m able to hit “Esc” and successfully bypass the test boot screen and get back to Windows.

This issue behaves very similarly for both Veracrypt and Bitlocker. Once I successfully get out of the prompt and into WinPE/recovery tools, input works fine. Input also works fine for a live Linux USB.

I’ve tried…

  • Different USB ports
  • Different keyboards
  • PS/2 to USB keyboard adapters
  • Using an Adruino device which typed out the password to emulate a keyboard
  • Tweaking various BIOS/UEFI settings

BitLocker actually did work for me for a while. The password prompt was fine. Then one day after a Windows update ran this issue cropped up again. I had to try and try until I could get to the recovery tools and manually decrypt the disk. I tested again today with the hope things were magically fine, but no. The preboot auth process is too finnicky for me to trust at this point.

I’m on an ASUS AB350 Pro4 with an AMD Ryzen 7 3700X

It seems I’m not the only person with this issue. Someone even has an identical CPU, and a potential fix of their own with UEFI settings, but it sounds like their “fix” seems not to have fully resolved things.