I recently installed Linux Mint and after several days noticed that the left mouse click wasn’t registering sometimes. After doing some research, I found that this was a common issue that Unix had and they seem to be trying to fix it (although that was in 2014/15).
Someone said that if you rolled back your installation then it might help. So I went to Menu > Administration > Timeshift (in Linux Mint Tara) and selected the earliest snapshot to restore from, which is several days ago when I first installed the system.
The system rolled back and so far I’ve not had any issues with the left mouse button. So if you’re experiencing a similar problem try rolling back and see! It’s worth a shot!