I have a latest cygwin installation (1-5-23-2) with the latest boost package (1.33.1-2). With the following test case... #include <boost/filesystem/operations.hpp> int main(int argc, char** argv) { boost::filesystem::path path1("/etc"); // ok boost::filesystem::path path2("/tmp"); // boom! } ...I'm seeing a crash when the second path object is created... 6 [sig] test 1652 C:\cygwin\home\admin\test.exe: *** fatal error - called with threadlist_ix -1 Hangup This problem didn't crop up until recently, but after rolling back to an earlier version of cygwin the problem persisted. To further confuse things, the problem does not occur on a different machine running the same cygwin version. I have run cygwin diagnostics (cygcheck), and everything reports OK. At this point I'm not sure if this is a cygwin issue or a boost issue or a machine specific issue, so I am posting to both groups in an effort to try and isolate the problem. What additional information should I be trying to gather? Thanks, Brian