I'm not understanding what possible benefit you'd derive from intentionally going out of your way, doing extra work, just to prevent your code from also compiling to 32bit. If we were getting into asm thunks that's one thing, since it's not simply LongLong vs LongPtr (an alias for LongLong in x64). But you're saying you want to use LongLong just so you *can't* compile to either 32 or 64, you *have to* do all your declares from scratch just so you can break compatibility?? For no other benefit, purely for not being compatible? And maybe also once every 10000 lines get to write 8 instead of Len(Of LongPtr)?