I'm also curious since it happened to me again recently. I'm still convinced Windows Updates has nothing to do with it since I haven't any Windows updates of any kind installed since December (actually, I restored an image from December on my machines since several updates since Decembers were breaking them and I got fed up).
I've 0nce faced a delay as described.
It wasn't an update file. It was the SEARCH for update that was running forever and kept the computer so busy that was causing the delays.
So I set, under services, WU to manual and on WU page to never check and the problem has gone.
Antivirus can block an action till it ends a scan.
Do you have Malwarebytes?
Quite old but...
https://www.********.com/2018/malwarebytes-big-problem/
Sorry, 7 forum it's modifying my link
Massive ongoing Malwarebytes issue affecting all users - Anti-Virus, Anti-Malware, and Privacy Software
Unfortunately antivirus is a "must have" despite I had never had a virus on my computer. All them slow down the computer.
On an old laptop with Win XP I found out that with antivirus and it's low memory, it's quite impossible to use. It has no antivirus and it works fine. (made a disk image for backup, just in case.)
I think a good firewall is more important than an antivirus. I have almost 10 attempts every day blocked by the firewall.
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