Hi Thank you for your extremely quick (and faster than support from any company..) reply. Sorry, can you give more detail ? >From the look of the error the 'mock centos5' is missing these files :- /usr/share/aclocal/ltoptions.m4 /usr/share/aclocal/ltsugar.m4 /usr/share/aclocal/ltversion.m4 /usr/share/aclocal/lt~obsolete.m4 - which come from libtool2 (on centos6) Centos5 obviously doesn't have that version... I noticed in the .spec file it has --------------------------------------------------------------- %build # aclocal workaround - to be improved cat `aclocal --print-ac-dir`/{libtool,ltoptions,ltsugar,ltversion,lt~obsolete}.m4 >>aclocal.m4 # Force use of system libtool: libtoolize --force --copy cat `aclocal --print-ac-dir`/{libtool,ltoptions,ltsugar,ltversion,lt~obsolete}.m4 >build/libtool.m4 --------------------------------------------------------------- Ilyas , it isn't the fact that I can't build Centos6 PHP 5.3.8 - that works fin in Centos6 - my issue is using the built src.rpm in mock so that it builds for Centos5. Thank you to everybody who responded. Regards _______________________________________________ CentOS mailing list CentOS@xxxxxxxxxx http://lists.centos.org/mailman/listinfo/centos