.NET Framework 3.5 stuck on Downloading required files (Windows 10 1903)

Hey.
I found how to fix the issue. I had same issue tried alot of things and nothing worked untill I looked up this.
Type Run in search then services.msc and then try to find Windows Update. 
If you can't find it on your list then this is what cause the issue. 

To get it back I followed instructions in this link - > 

https://www.tenforums.com/tutorials/57567-restore-default-services-windows-10-a.html

Find the Windows Update reg file download it from the page. then run it and restart your pc.

After restarting type Run in search then services.msc and then try to find Windows Update. right click properties start up type -> automatic and hit apply . 

After that you should be able to run the .NET Framework 3.5 installation and it should install... at least it did for me.

Hello, 

Please try these steps after creating a System Restore point:

1. Open Registry Editor by running regedit command.
2. Go to HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\AU.
3. Create/change the value for UseWUServer from 1 to 0.
4. Restart the Windows Update service.

Retry to enable .NET Framework. Once enabled, restore UseWUServer value to 1. 

If that doesn't works, download the Windows 10 ISO file and enable .NET Framework using this guide:

https://www.kapilarya.com/how-to-enable-net-framework-3-5-on-windows-10

In case you receive error 0x800F0954 with above method, open administrative Windows PowerShell.

Then try Add-WindowsCapability –Online -Name NetFx3~~~~ –Source C:\Temp\sxs command.

You need to replace C:\Temp\sxs with actual sxs folder location on your system.

Hope this helps!

Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.