Windows 10 ShellExperienceHost crashes

I've been struggling with this for days and went through hundreds of pages of solutions. Nothing worked, until I hit this page, where at page 22 user PaulSturm recommended to run a repair using Tweaking.com - Windows Repair Free/Pro.

I was obviously very suspicious of this, but quite a few people said it worked for them and I was willing to try anything after spending so much time with this, thanks to Microsoft's despicable support.

You will need to install it, start the application, restart in safe boot mode when it asks and then run the default selected repairs. No need for the pre-scan, sfc scan or anything outside the repairs section (other than the strongly recommended backup and system restore point). It took about 20 minutes for me but everything was back to normal after a restart following the repairs. I don't know exactly which fix did it, but it's the ONLY thing that worked for me.

Again, I don't expect you to trust me on this, but there are quite a few people on that Microsoft page that vouch for it. Make sure you're comfortable with using this and do make a backup and a system restore when asked.

Looking deeper at the problem, I was getting this error in the event log every time I clicked on the start menu

Faulting application name: ShellExperienceHost.exe, version: 10.0.10586.306, time stamp: 0x571afaa5
Faulting module name: Windows.UI.Xaml.dll, version: 10.0.10586.306, time stamp: 0x571af9f6

This event would appear after every time I clicked the Start Menu. I ran Process Monitor from SysInternals, clicked the Start Menu, and saw that ACCESS DENIED was showing for the User Accounts Package settings.dat for ShellExperienceHost. This file is located under:

%localappdata%\Packages\Microsoft.Windows.ShellExperienceHost_cw5n1h2txyewy\Settings\

(localappdata is the environmental variable for C:\Users\USERNAME\AppData\Local\)

I deleted the settings.dat file, clicked on Start Button, and it still wouldn't open due to settings.dat being deleted. So I renamed Microsoft.Windows.ShellExperienceHost_cw5n1h2txyewy (the entire folder) to .old and reinstalled the ShellExperienceHost UI App using the following PowerShell Command from an elevated PowerShell Window:

Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "C:\Windows\SystemApps\ShellExperienceHost_cw5n1h2txyewy\AppXManifest.xml"}

This then reinstalled the Local Package for my user profile, putting settings.dat back in place. Now no more errors and start menu is now working.

After months of trying to fix this, I was finally able to by downloading a .img (like a .iso) file for Windows 10 for the exact build number that I had installed (Build 10240).

Once I had the right .img file, I was able to use it to do an in-place upgrade to the same version. Trying to do the same in-place upgrade to the latest version kept failing at 40% with error 0xC1900101-0x30018.

My start menu, notification center and Edge are all functional again.

Thanks to @magicandre1981 for all your help.