Someone please help, I’ve been stuck since forever just trying to update.
I HAD TRIED:
-
running unity hub as admin
-
disabling firewalls & antivirus
MY SPECS:
OS: windows 10 version 21H1
RAM: 8 gb
HDD: (23.0 GB free) of 232 GB
CPU: Intel(R) Celeron(R) J4105 CPU @ 1.50GHz
GPU: Intel(R) UHD Graphics 600
I currently use:
Unity Editor version 2019.4.2f1
Unity Hub 3.0.0-beta.2
My internet speed is fine.
If this can’t be fixed, is there a manual way I could install the latest unit editor without using the hub?
like through zipped folders or something?
![1]

Check out the Unity Archive: Download Archive
I had the same error “Install failed: Validation failed” when trying to install the Editor via Unity Hub as a non-Admin user on MacOS (iMac 5k end 2015, Big Sur 11.6.1).
I re-tried as an Admin user and it perfectly worked.
Filed a bug report.
Maybe this applies to Windows as well(?)
I tried as administraton in windows and it didn’t work. I tried many things, and nothing seems to be working.
Hello!
We can’t really say why this is happening without seeing your Unity Hub logs which would have the information as to where it is failing and on what, but there are a few solutions that might help.
Yes like mentioned above, you can try Running in Admin mode and disabling any Firewalls or Antivirus Software as sometimes they can be the cause but there are few things more that you can try:
Allowing Unity and Unity Hub through the network proxy settings
Disabling any VPN or other IP-altering services when you’re using Unity
Essentially a VPN may sometimes cause issues with the Unity Hub most notoriously was the NordVPN one which was not caused by us and we are trying to collaborate with them regarding it, but sadly it’s taking unreasonably too long to fix/troubleshoot 
But if you still continue to encounter the issue please use the Unity Bug Reporter tool and there is a chance that the Customer QA Team might be able to provide a solution as to how you might be able to install the Unity Editor regardless of the issue.