OK now I really need help. I tried to install version 9.4.4-2 of Postgres with ftp://www.fruitbat.org/pub/cygwin/circa/2015/09/25/151012/index.html, but now it won't start. I also tried to install 9.4.4-1 but that won't work either. I also tried to exit all Cygwin processes and run 'dash' and 'rebaseall', but it didn't help. How do I install an old version of Postgres 9.4 to upgrade to 9.5? $ /usr/sbin/postgres --version postgres (PostgreSQL) 9.4.4 $ /usr/sbin/postgres FATAL: could not create shared memory segment: Function not implemented DETAIL: Failed system call was shmget(key=5432001, size=40, 03600). $ /setup-x86 -X -q -P postgresql-9.4.4-1 note: Hand installation over to elevated child process. $ /usr/sbin/postgres --version postgres (PostgreSQL) 9.4.4 $ /usr/sbin/postgres FATAL: could not create shared memory segment: Function not implemented DETAIL: Failed system call was shmget(key=5432001, size=40, 03600). http://stackoverflow.com/questions/36411485/how-do-i-install-postgres-9-4-on-cygwin On 4/4/2016 3:19 PM, Chloe wrote: > Can you please change the Postgres packages to use postgres94, > postgres95, postgres96, etc. names? Each version is incompatible with > the previous. This will allow installing Postgres in separate binary > directories to enable upgrades. Alternatively, please increase the > 'previous version' history to allow installing old versions. Setup > only has 1 previous version, and if the current version is 9.5.2 and > the previous version is 9.5.1, then there is no way (or very > difficult) to install 9.4! > > http://serverfault.com/questions/532379/how-do-i-upgrade-postgres-database-in-cygwin >