I'm having a problem trying to selfupdate MacPorts on my machine: the configure script stops on the following checking for Tcl configuration... found /usr/local/lib/tclConfig.sh checking for existence of /usr/local/lib/tclConfig.sh... loading checking for Tcl public headers... /usr/local/include checking for tclsh... /usr/bin/tclsh checking for Tcl package directory... /Library/Tcl checking whether tclsh was compiled with threads... no configure: error: tcl wasn't compiled with threads enabled I currently have MacPorts 1.5.0 installed from the .dmg archive. My version of tclsh was 8.4.10 in /usr/bin and probably indeed it was not compiled with threads. So I installed the MacPorts version of Tcl (sudo port install tcl) thinking that this one would be compiled with threads enabled. This installed version 8.4.15 in /opt/local/bin. Then trying again to "port -selfupdate" Same error and still the configure script finds tclsh in /usr/bin checking for tclsh... /usr/bin/tclsh So I changed the /usr/bin/tclsh symlink so that it points to the newly compiled tclsh: lrwxr-xr-x 1 root wheel 20 Sep 1 14:12 /usr/bin/tclsh -> /opt/local/bin/tclsh Still I get the same error from the MacPorts configure script. How can I get out of this ? How do I do to have tclsh compiled with threads enabled? Apparently even with the MacPorts version it is not. I found the following line in /opt/local/lib/tclConfig.sh: # Flag, 1: we built Tcl with threads enables, 0 we didn't TCL_THREADS=0 And why is the MacPorts configure script looking for the wrong Tcl. It is loading /usr/local/lib/tclConfig.sh. TIA Bernard