P: slideshow - images rendered as swapped blocks

I tried rotating them but it didn't fix it for me, deleting and re-importing them fixed it for one of the images but the problem just occurred for another one. Happens on about 3 images out of 40. Since 2/3 of them are virtual copies with adjustments it is really cumbersome to delete and re-import and redo virtual copies, redo slideshow order etc.

Looks like some crop-rotation is related to this bug - changing rotation - seems to fix it, or exporting picture and than importing an edited version back to slideshow seems to help, as a temporary workaround...

I have Radeon R9-200 and latest drivers (14.500...) installed already.

I have the same problem after upgrading from 5.6 to 6.0 - my graphics card AMD Radeon HD 7450 has the latest drivers. Never had a problem on 5.6, I've also unticked the option in Lightroom to use the graphics card for performance.

Unfortunately I cannot downgrade the lightroom catalog back to 5.6 - does anybody have ideas to resolve this?

That's a common video card driver issue.
Make sure you updated your video card driver from the GPU maker's website.