Kirk,
Windows 7 Home Premium x64, PM Version 5.0, build 15800 (e6ecc1c).
I have recently been getting red artifacts on some of my .jpg images, many of which are b/w historical photos. I've tried switching color management on/off, but nothing changes (quitting and relaunching PM doesn't help). When I view the images in IrfanView they look normal. Photos of text (restaurant menu's, exercise diagrams, etc.) also show the red artifacts.
On my backup computer everything looks normal. I exported the PM preferences from my backup computer and imported them into my primary computer but that hasn't changed a thing.
The monitor on my primary computer is a NEC LCD 2490WUXi and I haven't changed anything on it for months.
I can send a couple of .jpgs to you for viewing if that would help.
Many thanks,
Warren