That is frustrating!
Many Windows 10 user have this problem, and there are a few things you can do that can fix the problem. You can do each of these steps independent from each other.
Sorry for stating the obvious, but restarting your computer does fix by far most of the problems, and people don’t always think about it.
Did you not yet restart your computer? Try this first.
Check for updates
Windows constantly releases updates and some updates might be fixing the issue that causes your start button not to work.
By default Windows will install updates automatically, but if your settings are changed, then follow the steps below.
Make start menu full screen
Sometimes the Start menu is just kind of ‘stuck’, and you can unstuck it by changing some of its settings, like switch the Start menu to full screen, or changing the mode to Tablet mode.
Change your computer to ‘Tablet mode’
Run the Start Troubleshooter
A troubleshooter is a program that runs and checks on your computer why somethings specific isn’t working.
Microsoft has a troubleshooter to check what might be causing the Start menu not to work.
You’ll need to download the troubleshooter and then run it.
Go to this Microsoft Page.
Click on ‘Try the troubleshooter’, and then on ‘Start menu troubleshooter’.
Now the start menu troubleshooter should be downloading.
You’ll see the downloaded file in the down left corner of your screen.
Click on it.
When the window opens, click on ‘Start Menu’.
Now the troubleshooter is checking if it can find any problems.
If it finds any problems, follow the instructions that the troubleshooter gives.