You might try doing a ps -auxw from a console window and see if perhaps Fritzing (or other applications) aren't exiting successfully and are holding files open that block new starts. The stray tasks will get killed on the reboot. If there look to be stray tasks after you close Fritzing you can use the kill command with their pid to kill them and see if Fritzing will then restart without the reboot (just be careful that you know what you are killing 
).
Peter