The Preview app in macOS 12.6 can only open 24bpp BMP files. It can not open BMP files less than 24bpp. This last worked in macOS 12.5.1. When I try to open a BMP file that's less than 24bpp, I get the following popup:
This is a critical issue. Thank you.
MacBook Pro Apple Silicon
After spending several hours on chat and phone support this afternoon, the final Senior Advisor consulted with "Media Creation" and was told that they were surprised to hear that any version of Monterey had displayed <24bit images in FInder or Preview. It was clear that this issue was a feature, not a bug. That is, Apple intended to drop support of <24bit images. But wait, there's more. When I mentioned to the Senior Advisor that my laptop was telling me that the 12.6.1 update was available but I'd not installed it in the middle of trying to resolve the BMP issue, he suggested I go ahead and install it, because it might very well help. I suspect it was more of a "it couldn't make it worse" suggestion. Anyway, I did the 12.6.1 update and after the reboot, my 8bit BMP images are viewable with Finder, Preview, and a third party app, Pixea, none of which were displaying these images 2 hours ago..
So I have no idea whether Apple intended to drop support for <24bit images, released a bug in 12.6 (ish), doesn't bother keeping its support staff informed, or all of the above, but 8bit BMPs are now working on my MacBook Pro (M1) with 12.6.1. Probably lose it again when 12.6.2 is issued...
Anyone know how this is playing out in Ventura?
Monterey 12.6 Preview app cannot open bitmaps!
