Apologies for the troubles due to Lightroom CC2015.2.1
Would suggest you to disable "show add photos screen" under Lightroom Preferences> General tab and then, restart Lightroom and check again.
If that does not help, you might have to roll back to Lightroom CC2015.1.1 : Instructions to roll back to a prior update version
Sorry, didn't mention that I had already done that also. I also found the file that controls the gpu to confirm it was written to "false". I can't remember where it was because I don't have my tracking noted with me but found a post that showed where it was and if it was confirmed. It's very strange that both of my 3 sets of fans escalate and deescalate as I work on files. As if the gpu WAS on in prefs. But I assure you, it's not.
Sent on the new Sprint Network from my Samsung Galaxy S®4