Question White underscore (not blinking) for 15+ seconds before boot and other possibly related issues.


Sep 17, 2011
I recently built a new desktop PC about a week ago and after a Windows Update yesterday, I noticed that a solid white underscore showed up for 15+ seconds before the PC started booting. After trying a few different possible fixes like turning off CPU/GPU overclocking and undervolting and reverting to past restore points, I have yet to find the cause. At one point, I also got a BSOD for an Invalid Process Attach Attempt.

Basic PC info:
MSI MEG B570 Unity Motherboard
Samsung 970 EVO SSD
Corsair Vengeance 32GB(2x16GB) DDR4 3600 RAM
AMD Ryzen 7 5800x CPU
MSI AMD Radeon 6700 XT Mech 2X GPU
Corsair HX750i PSU
Windows 10 Pro Build 20H2 Version 19042.906

  1. Booting in safe mode fixes the issue, so I've narrowed it down to a startup service, just not sure which one.
Last edited:


Win 10 Master
Invalid Process Attach Attempt.
that is an unusual BSOD

Can you follow option one on the following link - here - and then do this step below: Small memory dumps - Have Windows Create a Small Memory Dump (Minidump) on BSOD - that creates a file in c windows/minidump after the next BSOD

  1. Open Windows File Explorer
  2. Navigate to C:\Windows\Minidump
  3. Copy the mini-dump files out onto your Desktop
  4. Do not use Winzip, use the built in facility in Windows
  5. Select those files on your Desktop, right click them and choose 'Send to' - Compressed (zipped) folder
  6. Upload the zip file to the Cloud (OneDrive, DropBox . . . etc.)
  7. Then post a link here to the zip file, so we can take a look for you . . .
I assume you mean X570 as B570 is a weird hybrid of B550 & X570 - the differences between both boards isn't very big, I assume a B570 would have a PCIe 3.5 speed slot, a slot that doesn't exist :)

Tried getting latest chipset drivers?
Tried updating BIOS on motherboard?
Tried updating GPU drivers?

Booting in safe mode also just shows it could be a driver.