First of all, it can be compiled even with Boost 1.80 just fine. Second, the error is self explanatory: filesystem exists in both namespaces, boost and std, in your case because you're compiling with -std=c++17 or something like which Orbitcoin has no need for. That's because filesystem has been Boost only library until they merged it into ISO C++ as of C++17. Either remove it or enforce boost::filesystem where the compiler wants you to.