Attention Map Makers,
As explained here: StarEdit Deprecation in Patch 1.23.0 we’ve recently deprecated our support for StarEdit in favor of SCMDraft 2. We’ve been working towards this (in collaboration with the author of SCMDraft 2) for the last couple of years. SCMDraft 2 is a widely used and superior map editor, and we decided that our engineering resources were better allocated to focusing on the game itself rather than competing with our community.
However, if you are still loyal to StarEdit please find the last working and publically available version for download here: http://download.blizzard.com/pub/starcraft/StarEdit/StarEdit.zip
Please note that StarEdit is no longer officially supported by Blizzard, and in future it is possible that it may stop working entirely due to changes in the game engine.
Once again, thanks for all of the fantastic custom content over the last 20 years!