The good news; previously written 64 bits are still valid! All fixes appeared to be possible in code, no versioning patches needed. :) That also removes the I AM STUPID 64 bits ban from the code. The bad news: I couldn't get a 64 bits Blender running here (ghost-mac issues... it has to be recoded using Quartz to be able to run 64 bits). So what I have tested was: 32 bits binary: - Appending/linking data from 64 bits file. - Reading 64 bits chained library-linked files (file -> file -> etc) - Linking 32 bits files with 64 bits files This has to be tested for 64 bits too. Will drop in IRC now to help.