Windows 10 (latest), latest Titan download, Dual EVGA 480's. Sometimes (not all), I can't build a 5th Catalyst. Just get a red image like something is in the way. Nothing exists or has been built near it. I try the build area command, no dif. Try to spin the catalyst, no dif. Any ideas?
Something I discovered in my recent game is did you have a mass point under that Catalyst? Even though it's unbuilt? If you have a unit that is trying to build mass extractors and building one under the Catalyst is in it's queue, it'll forbid you from building the Catalyst until you stop all fabricators that might try to build a mass extractor near it's location.