Hey,
I just created a community account to reply to this thread.
We just had a client experience this issue on a several computers at once.
The user profile and system permissions somehow got messed up during the update process. The stations with Norton Internet Security (SONAR enabled) experienced these issues, meaning the antivirus program might have thought some system changes that the update
was doing were malicious and blocked them.
One way we solved it on several computers was to do a system restore to a point before the update was applied.
Since you can't left-click start, right-click on it and click "Run" then type "rstrui" (no quotes) to get to the system restore app.
Once that finishes and the computer restarts. If your start button works again, we decided to hide/ignore that update (for now...until they fix whatever is breaking everything). We downloaded and ran this Microsoft "Hide or Show Updates" troubleshooter
package (LINK to help page or
DIRECT LINK to the file download)
We had one system where even after the system restore was complete, the start menu and permissions STILL didn't work.
We fixed that system by downloading the update on its own (HERE), disabling all antivirus/firewall/security software, then installing the update
manually. Once the computer reboots, the issues were still there but this time when we did another system restore (from an earlier restore point at the end of December) everything worked again.
I hope this helps someone get their windows 10 fixed without needing to do a full reinstall or Windows reset!
