Weird artifacts when zooming in/out

[twistless]

Something weird started happening after downloading the latest update to Illustrator...

I'm getting large dark grey artifact looking shapes (and a weird white line at times too) that appear covering half of my image (and a good amount of the art board). I can make them go away if I turn the layer on and off. But it shows up again (as a similar weird shape) if I zoom in or out. Then I have to toggle the layer on and off again to make it go away.

This is beyond annoying and making Illustrator virtually unusable. This file has a jpg (saved for web out of photoshop) on the bottom layer, but I'm not sure how that should be a problem as I've used this same process to trace pictures/photos for going on 2 decades.

Is anyone else having this issue? A temporary workaround?

See attached images for examples of how it appears.

[barbara_a]

This is not normal for Illustrator. First determine if it is happening on multiple Illustrator files. If it is only one file, that file is probably corrupt. Try copying everything in the file, creating a new file and pasting into the new file.

If this is happening on multiple files, I would start with some general troubleshooting techniques:
Close and reopen Illustrator

If that doesn't work, reset the preferences file. How to set preferences in Illustrator

If that doesn't work, use the Adobe CC Cleaner tool Use the Creative Cloud Cleaner Tool to solve installation problems