Change the USB port

Sometimes you can trigger Windows to pick up the mouse again if you plug it into a different USB slot. This forces the OS to register the device again and hopefully have it working as it was. This is a little hit and miss but as it only takes ten seconds, it is worth trying as long as you have a spare USB slot. Swap it with something else otherwise. Try right click

I had an issue where the mouse buttons swapped sides for no reason at all. Left click turned into right click and vice versa. Type ‘mouse’ into the Search Windows box and select ‘Configure mouse settings’. In the new window, select ‘Additional mouse options’ in the center under Related settings.

Make sure ‘Switch primary and secondary buttons’ is not checked. If it is not checked, check the box and hit Apply. Then uncheck the box and hit Apply once more. Remember to use the opposite button! The Best Mouse For Macbook Air Or Pro Read More

If none of those work, we need to dig a little deeper. SFC scan

Performing a System File Check (SFC) scan can help detect any issues with Windows that could be causing your left mouse button to not work. It is a self-contained test that is run from the command line. The SFC checks all Windows files and makes any repairs if it finds issues.

Right click the Windows Task bar and select Task Manager. Select File and Create new task. Type ‘cmd’ into the box and check the box to create the task with administrative privileges. This last is important. Finally, when the black box appears, type ‘sfc /scannow’ and hit Enter.

The scan may take a while but will look after itself. If the scan finds any issues, it will automatically repair them. With any luck, you will see a message that says ‘Windows Resource Protection found corrupt files and successfully repaired them.’ You may see ‘Windows Resource Protection did not find any integrity violations’. This is okay too as it shows Windows is working (mostly) okay.

If you see a message that says ‘Windows Resource Protection found corrupt files but was unable to fix some of them.’ then you will need to manually fix the issue. In the same CMD window as above, type ‘Dism /Online /Cleanup-Image /StartComponentCleanup’ and hit Enter. Then type ‘Dism /Online /Cleanup-Image /RestoreHealth’ and hit Enter. Allow both processes to complete and then reboot.

If that doesn’t work: App registration

Apps play a significant role in Windows 10 so our final tip is to force Windows to re-register all apps running on your computer.

Open a CMD window with administrator privileges as above. Type ‘Powershell’ and hit Enter. The prompt should change so it says ‘PS C:\windows\system32’. Then paste ‘Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register “$($_.InstallLocation)\AppXManifest.xml”}’ into the window. You should see a list of apps being processed and the task should complete within a minute or two.

Make sure you have Windows Firewall running when you run this command otherwise all you will see is red errors. Apps are tied very closely to Windows Firewall for some reason. Even if you don’t use the firewall, enable the service, run the command and then disable it again.

Those are the ways I know to fix the left mouse button not working in Windows 10. I have yet to come across a situation where one of these hasn’t fix the issue. Got any other fixes? Tell us about them below if you do.

Thanks for your reply, but my problem is not hardware related. This only happens with Firefox, same url, same page, all working like charm with Edge or Chrome.

I found 'uBlock Origin' extension keep prevent to click on several links. I switch to 'AdBlocker Ultimate' instead. Problem solved.