I type port upgrade -R libpng then first port tries to upgrade netpbm (and fails) port upgrade -R libpng ---> Fetching netpbm ---> Attempting to fetch netpbm-10.26.44.tgz from http://downloads.sourceforge.net/netpbm ---> Verifying checksum(s) for netpbm ---> Extracting netpbm ---> Applying patches to netpbm ---> Configuring netpbm ---> Building netpbm with target {} rror: Target org.macports.build returned: shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_graphics_netpbm/work/netpbm-10.26.44" && gnumake messages=yes " returned error 2 .... Then it upgrades libpng Error: Unable to upgrade port: 1 ---> Fetching libpng ---> Attempting to fetch libpng-1.2.22.tar.bz2 from http://downloads.sourceforge.net/libpng ---> Verifying checksum(s) for libpng ---> Extracting libpng ---> Configuring libpng ---> Building libpng with target all ---> Staging libpng into destroot ---> Packaging tgz archive for libpng 1.2.22_0+darwin_8 ---> Deactivating libpng 1.2.21_0+darwin_8 ---> Installing libpng 1.2.22_0+darwin_8 ---> Activating libpng 1.2.22_0+darwin_8 ---> Cleaning libpng and retries to upgrade netpbm with same error ---> Building netpbm with target {} Error: Target org.macports.build returned: shell command " cd "/opt/local/var/macports/build/_opt_local_var_macports_sources_rsync.macports.org_release_ports_graphics_netpbm/work/netpbm-10.26.44" && gnumake messages=yes " returned error 2 ........ still tries... Error: Unable to upgrade port: 1 ---> Building netpbm with target {} and retries... then tries to deactivate already deactivated version of libpng ! Error: Unable to upgrade port: 1 ---> Deactivating libpng 1.2.21_0+darwin_8 Error: Deactivating libpng 1.2.21_0 failed: Active version of libpng is not 1.2.21_0+darwin_8 but 1.2.22_0+darwin_8. Why this strange behaviour ? (PS: I keep the complete log of the session for who wants it) -- Erwan