How do I restore Windows 10 Start button functionality?

Question

Although this question seems like a dupe of this and this, the accepted answers to those questions did not work for me. Those questions/answers are a few years old now, so my problem that happens to fall under the same question may need an updated answer.

Problem/Question:
After a recent Windows update (delayed by several weeks due to insufficient disk space), 1) the Windows Start button does not work, 2) the search bar does not work, 3) the date/time widget does not work, 4) the notifications icon does not work.

How can I restore these? Of the stated, I'm most interested in restoring the Start button.

This may be a relevant observation: by running Task Manager, I observe that each click of the Start button (as well as the other three problem items) is followed by the creation of a "Windows Problem Reporting" background process. The process dies quickly: within 1 - 3 seconds, and no corresponding visible window/UI is generated.

What I have tried:

1. Get-AppXPackage
   I entered the following from an admin-privileged PowerShell CLI:

   Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}

Result: Start menu functionality was not restored after the command completed or subsequent reboot.

2. Booted into safe mode
   Per the instructions at this site...
   https://www.techmesto.com/fix-start-menu-broken-windows-10-technical-preview/#comment-144567
   ...I booted into safe mode.
   Result: Start button functionality was restored during the safe mode session but resumed to the described nonworking state upon subsequent resumption of non-safe mode. It is not an acceptable solution for me to work continuously in safe mode because of the various features disabled therein.

3. Cold boot
   I'm not entirely sure how/when cold booting really occurs on modern Windows PCs because there are so many more software layers between the OS and metal than I've been able to keep up with...but I have a vague, possibly mistaken, impression that holding down the power button for some protracted length of time, like 20 seconds or so, will trigger a cold boot. I tried this.
   Result: Start button remained non-working upon subsequent return to desktop.

4. Disabling fast-start
   As described at various websites, including this one...
   https://windowsable.com/how-to-enable-or-disable-fast-startup-in-windows-10/
   ...I unchecked the "Turn on fast startup" checkbox in Control Panel's Power Options.
   Result: Start button remained non-working upon subsequent return to desktop.

Windows Info:
Edition: Windows 10 Pro
Version: 1803
Installed on: 09/30/2018
OS build: 17134.320

Plea for Help:
Can any knowledgeable community members please suggest ways to diagnose/fix the problem? I'm particularly curious what's going on with that "Windows Problem Reporting" process - can it reveal what's going on? If so, how can one access it given that the process starts and dies in a blink without any human-interactive UI?

Answer 1

Since Windows 10 v.1809 is being released tomorrow, the simplest fix is to create Windows 10 installation media as an ISO image, installed on USB or DVD, and use that to update and repair Windows, keeping current files and applications.

You'll have both repaired the issue and accomplished the update, which would inevitably be pushed on your PC anyway. However, make a complete, verified disk image before updating, lest the process mangle the OS or whole system.

Answer 2

See if you are in tablet mode by entering Win+A, click Expand, and if "Tablet mode" is selected then click on it to deactivate.

Another advice that sometimes works is to go to the folder C:\Users\[yourself]\AppData\Local\Microsoft\Windows and rename the Windows folder to something else and reboot. Log out and in, and Windows should regenerate the folder. Return the folder if this didn't help.

Another possibility is to use regedit to navigate to HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\Advanced, create a new DWORD (32-bit) value and call it EnableXamlStartMenu, then log out and in again.

Another is to press WinX on the keyboard and select "Power Options", click "Choose what the power button buttons do", click "Change settings that are currently unavailable", uncheck "Turn on fast start-up" and click "Save changes".

As last resort, install the Start menu replacement of Classic Shell.