Unity Project Running Slow (After running smoothly for months)

Good afternoon, Unity Community,

My question is if anyone has had a project start to run slowly on them a day after it was running smoothly? I have a scene that contains dozens of sprites that I want on screen at the same time and sometimes that scene runs a skip or two behind what I would like but the rest of my scenes are very simple (visually) and have never given me any lag or a slow speed while in Play Mode.
Yesterday I saved one of the more simple scenes (as well as the project), went to bed, and awoke this morning to find my scene camera changed and a very laggy Unity Editor. I’ve already fixed the scene camera but I can’t seem to speed Unity back up to what it was before, whether on a simple scene or a complex one. I click play and lag is all I get.

It is worth noting that Angry Bots gives me lag as well. Not nearly as bad as the current scenes I have, but lag nonetheless. (and it usually runs perfectly)

As far as hardware goes, I have an MSI GE70:

CPU: Intel Core I7-4700MQ
GPU: Nvidia GeForce GTX 765M/2GB
RAM: 12GB DDRIII

I’ve already tried a restart (among other things). I’m tempted to uninstall Unity and reinstall it… Any thoughts on what it could be?

Delete your temp folder and library. If the problem still persists then it may have been around for longer than you think.

The fact that it affects other projects leads me to believe you changed some editor preference or your harddrive developed a few bad sectors over night.