Can you please share the screenshot of the images which are corrupt?
Also, try and export those images and check how they look outside Lightroom.
Turn off the GPU option on the Performance tab of the LR Preferences.
Have tried that already! Still happening.
It looks the same as all the other posts about LR and corrupt images, part of the image suddenly goes white with lines etc.
Upon export it exports looking the same as the preview. When they have previously exported just fine.
This is a corrupted file, caused by some hardware malfunction. THe obvious place to look is to see if the hard disk is failing by running diagnostics on it. Other possible causes include bad memory chips in the computer.