Go here:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s
Search for the text "stealth quote" in there. Click the link. Read what it says.
Others have reported this issue with being signed in or not on YouTube. I've very
briefly tried a couple of things when I've been logged in on YouTube & it doesn't stop my
downloads with VDH. Now, you must understand, my login on YouTube is just my generic
Google login. I do not have one of those premium YouTube accounts or one of those
YouTube TV accounts they're always pushing at you. I don't know if that makes any
difference. I haven't tried private browsing. I have had multiple YouTube downloads in
progress concurrently & that works fine.
The ownership thing is a bit of a shot in the dark. I'm the only user on my system as
well & I'm in the administrators group. Yet I found reason years ago to take ownership
of my boot partition anyway. I can't exactly remember now what the reason was. It was
too long ago. I believe I was encountering directories on my boot partition that Windows
kept telling me I was not allowed to access. Yes, despite my being an administrator. So
instead of fixing the permissions piecemeal directory by directory, I just did the whole
partition. There were still a few directories that it wouldn't process. I suspect those
might have been symbolic links. There are a few symbolic links on the boot partition. I
think they're intended to be aliases, alternate names by which you can refer to certain
directories. I didn't create them. They seem to be how Microsoft builds the partition.
In any case, I went through the exercise & my system still runs fine. Maybe this is a
red herring.
I'm looking again at the error message you posted in your first post upthread. I see
this:
ffmpeg version N-91146-gfe84f70819-vdhcoapp Copyright (c) 2000-2018 the FFmpeg developers
built with gcc 7.3-win32 (GCC) 20180312
Just for grins & giggles, I just did this:
C:\Program Files\net.downloadhelper.coapp\converter\build\win\64>ffmpeg
ffmpeg version n4.1.5-vdhcoapp Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 9.3-win32 (GCC) 20200320
As you can see from the prompt, this is the captive ffmpeg distributed with VDH. I have
the real ffmpeg elsewhere on my system but this is what I'm getting from my version of
ffmpeg inside VDH. I have been under the impression that the captive ffmpeg is inside
the CoApp. But I just inspected the CoApp installer application using an unzip
application & there's no ffmpeg in there. So it must be the case that the captive ffmpeg
is actually packaged with the VDH extension. I'm running the latest beta, version
7.6.3a6. You might try that. I've been using it since Michel released it a couple of
weeks ago & it hasn't given me any problems. In fact, it's solved some livestream
problems for me. There's also a few minor mainly cosmetic improvements in it. I say
it's worth a shot.