Q. Where to download Start Menu Troubleshooter for windows 10 ????

Answer.

Unfortunately, the official Start Menu troubleshooter is no longer available. There is no official statement from Microsoft yet, but you can refer this support article to fix issues with Start Menu:

In case if issue still persists, try to re-register Start Menu using these steps:

1. Open Task Manager, click File > Run new task. 

2. Type PowerShell in the Create new task box. Check the option ‘Create this task with administrative privileges’. Click OK. 

3. In the administrative Windows PowerShell window, type/paste following and press Enter key: 

Get-appxpackage -all *shellexperience* -packagetype bundle |% {add-appxpackage -register -disabledevelopmentmode ($_.installlocation + “\appxmetadata\appxbundlemanifest.xml”)} 

4. Let it complete and then restart your system.