Right click not working on SL, and other strange behaviors

Hi! 

Every 20 minutes or so after starting working on a file Storyline starts behaving strangely - the right click commands won't work properly. Eventually, after trying to save, the error "Tre project file could not be saved. Invalid window handle" will appear. 

I need to keep closing and opening the project again and again to work for another 20 minutes, until it starts all over again.

 

I'm working locally, the file is on my desktop with the shortest name possible, I've reinstalled Storyline and restarted my computer, but that gives me just a couple of minutes more of work, until the error starts again.