I have been unsuccessful at merging Leica M Monochrom Typ 246 raw images. Leica M Typ 240 color images - no problem at all. I have started a chat discussion with Adobe, and the local Leica store actually duplicated the problem on their computer. I am using Lr 2015.6 Windows 10. I have tried 2, 3 and 4 images and always get the same message: "Unknown errors occurred" Merge using Photoshop CC does work with the Monochrom images