Command window pops in and disappears ~3 min after starting

This pertains to 21H1, Build 19043.1165.

Sometime in the past week - can't nail down the precise day - about 3-5 minutes after I've logged into Windows (HP laptop), a command window will pop up, then disappear in a second or less. Too fast to capture, screenshot, or notice what's going on.

It never did that before, nor does my home desktop machine do that.

What could it be? What in the event viewer might help me figure out what is happening?

Try3 said:

I suggest that you start video recording your screen with your mobile phone after bootup then, when you capture the window, reading its contents and its window title.

There might be something in Task scheduler records that matches the occurrences.

Denis

Good guidance. I will do my level best to shoot video next time I start - will just do in the morning so I keep the routine the same. Regarding the other great idea, yes, Task Scheduler showed that something called HP Jump Start launched as I logged in. Its description - "HPJumpStartLaunch launches various components of the HP JumpStart application. HP JumpStart is a welcoming companion that helps users own their device through registration, take control through app selection, and master it with tips and advice." - doesn't exactly make it sound useful, so I stopped the process, and also disabled it from starting with my computer. We'll see where that takes me.

I followed the suggestion to take cell phone video of the command window popping up. Here is the screen shot of the window:



It appeared 2:20 into the video, which I started taking as I hit enter after typing my Windows password. I'm not very adept with video or with cell phones, so I couldn't surgically dissect what had happened. I was unable to see an actual command appearing in the window - just what is seen there. That doesn't prove no command appears, just that I couldn't find it. Window is there for no more than a tenth of a second (my guess).

Since I believe that's what a batch file, with @echo off, might produce, how would I find the relevant .bat file? I have many on my computer.

Per dalchina, I did download autoruns. Is there a way, in that, to segregate types of things that would have launched the command window, specifically a batch file?

Or what's a good way for me to get the full-resolution video from my Pixel phone to my computer, and into a utility where I can go frame by frame?

dalchina said:

In Autoruns, try Entry, Find, .bat and F3 to find next.
I.e. use its search feature. Try finding cmd.exe too.

Try a process of elimination.
Does this appear after a clean boot?
If not, reenable items progressively to identify the one it's related to.

I could find no .bat instances using this method. Found four cmd.exe instances, and all were associated with Microsoft Defender, and last run on 8/4, 3+ weeks ago.