Look into the flickering screen issue associated with Outlook and iMac 2015
There is an issue that others seem to be having when using Outlook on a late 2015 iMac. We have 3 employees at my company with late 2015 Retina 5K iMacs (27", 3.2GHz Intel Core i5 Processor and 8GB 1867 MHz DDR3 Memory) whose screens will flicker and turn white/black, but when they restart it fixes the issue for a day. Then it happens again. It seems to happen when Outlook is open, which we are constantly using, and from another forum, it seems to be happening to many other people with this same exact model iMac and Outlook. Apple suggests resetting the SMC and the NVRAM (which I have done for all computers) and then running a diagnosis. I have not run a diagnosis yet, but from what your forum says, it doesn't seem to come up with anything anyways. Please look into this! Thank you!
the last few days the screen flickers about 10 times when i open an email and runs very slow. what happened?