myodbc_end really should only be invoked during Windows DLL unload, since it's not connection-specific and not thread-safe either. This bit of brain fade accounts for our bug #185343 and several bugs filed at mysql.com. diff -Naur mysql-connector-odbc-3.51.14r248.orig/driver/handle.c mysql-connector-odbc-3.51.14r248/driver/handle.c --- mysql-connector-odbc-3.51.14r248.orig/driver/handle.c 2007-03-07 18:56:40.000000000 -0500 +++ mysql-connector-odbc-3.51.14r248/driver/handle.c 2007-04-20 13:12:25.000000000 -0400 @@ -121,7 +121,6 @@ GlobalFree(GlobalHandle((HGLOBAL) henv)); #else if (henv) my_free((char*) henv,MYF(0)); - myodbc_end(); #endif /* _UNIX_ */ return(SQL_SUCCESS); }