random black squares

Most likely a video card/driver problem.  Try turning off graphics processor in preferences/performance.

I am having the same problem ... definately not a card reader issue as I am working from my hard drive ... did you get an answer?
Toby

Same advice, probably graphics card or driver.  If turning off GPU helps then turn it back on and go into Advanced Settings and set it at Basic and see if it works there.

Worked, thank you!