Crop mode Preview Constantly Flashing?

[FilmPerson]

Ok, so I just got my 50d and I've been having a lot of success teaching myself some things, but there's one problem that I just can't seem to solve.  When I follow tutorials for shooting in crop mode my preview image is bright pink! The preview is also in a different resolution from what's actually being shot.  If anyone can clear this up for me I'll be eternally grateful.

Edit: I've upgraded since and now my raw preview is flashing between 2 different aspect ratios.  Does anyone know how to fix this?  I've been asking other people and they've had similar issues

[Andy600]

I know it's a long read but this has all been covered in the main 50D raw thread: http://www.magiclantern.fm/forum/index.php?topic=5586.0

If you have pink previews you are likely using a very old build! If not, check if sticky half shutter is enabled.

The preview size difference is because you are viewing at 5x and shooting 2.475x - There is a crappy low FPS/greyscale preview mode in the raw module settings that will let you frame your shot correctly but it's no good for focusing or shooting with TBH.

[FilmPerson]

Alright thanks, i upgraded to a more recent nightly build.I got preview mode to work in black and white now, but the screen is flashing the whole time so it's impossible to use.  I've been reading that thread for a few days now but haven't found any solutions, you know what's going on? Thanks for the help