Likewise; just updated B4X. Reinstalled the SDK, re-added some libraries. And whether in release or debug mode, the app crashed immediately on start up, with nothing showing at all in the logs on the PC, whether filtered or not.
Updated: I loaded a smaller app, which uses far fewer libraries, and that works just fine in 10.7. So I'm guessing there is some incompatibility with *something* that's causing this issue. But without an error message, or the logs, it's going to be fun to find...