<<I suspect it is some sort of conflict between libicu linked into fbintl and libicu used in the macOS system frameworks (and I suspect a change to icu in macOS is why this only started with 10.13). I tried to rebuild Firebird with a later version but didn't get very far>>
MacOS does not use a full icu implementation, so I doubt you are linking against the system icu lib (/usr/lib/libicucore.dylib) unless of course you are specifically requesting it. To be honest I doubt you could build Firebird if you hadn't installed a proper copy of icu from elsewhere. Personally I expect the problem is elsewhere... Does it crash on 10.13 or on earlier versions of the OS? Have you analysed a crash dump? What happens if you use isql on your embedded version of Firebird? What version of Firebird are you using? Paul
