Black/White images in Photoshop, no picture, just box with black or white

[wendyfern]

I have a Mac desktop running el Capitan and Photoshop CC2018. It is over 2 years old, and has 32GB of RAM. Its hard drive has 296.63GB free out of 499.05GB. The last time I shut down was last night. I rarely run a cleanup program.  When I have been working in Photoshop for awhile, and I either open an image, or click on an existing image, the image comes up totally white or totally black.  Turning Photoshop off and then back on resolves this for awhile, but then it starts doing it all over again.  Any answers?

[Damien Symonds]

Hi Wendy, it might be akin to the old "black boxes" problem.  Try this: https://www.damiensymonds.net/2015/09/black-boxes-and-other-weird-behaviour.html

And yes, try to run CleanMyMac regularly: https://macpaw.com/cleanmymac