All versions of MeGUI after v2924 don't show 6 pixels worth of image in the preview window. The affect of this is that if there are black borders on the right side that are less than 6 pixels wide then that fact is obscured leading to those pixels not being cropped and black borders remaining on the right side in the output file.
MeGUI 2924 x64
I can't reproduce the problem with MeGUI32,64 or 6666, using DGindex, ffms2 or Lsmash decoders. It is ok for me.
You need upload a sample to check it.
Well I know I wasn't the only one that experienced the issue, it was also mentioned here:
https://forum.doom9.org/showthread.php?p=1965672#post1965672
https://forum.doom9.org/showthread.php?p=1975335#post1975335
I didn't try MeGUI32 but the issue happened with both LSMASH & DGIndexNV. A sample wouldn't matter because the issue occurred with every sample I tried. Clean script with only source filter. Mostly DVD sources.
When I reported the issue I was still using Windows 7, though I'm not sure how that would affect it. However I just built a new PC with Windows 10 and retesting v2944 & the new v6666 on that machine I can't reproduce the issue now either. I'll retest on my Windows 7 laptop when I get a chance and see if the problem still persists there.