More on 10.12/10.13 crashes

[quote=371168:@Tim Jones]That’s what I was originally using -

Self.cvFile.Backdrop = NSWorkspaceMBS.iconForfileType(extension(Self.st_CurrentFileNameText)).CopyPictureWithMask

That still provided the corrupted image shown above. Using Trixie’s solution has resolved it on 10.12 / 10.13.[/quote]
I would suggest looking into the copyPictureWithMask routine, for displaying icons in the apps I develop, I use NSWorkspace declares to obtain NSImages and then either I draw these images myself or I draw them into a Xojo picture to use in the Xojo app.

Multiples of 4 is something that I also encountered with Apple’s vImage framework, it’s at least documented that it only works ‘correctly’ with multiples of 4.

That’s basically what Trixie’s method above does.