Mattermost 5.2.2 no window opening on MacOS when starting

Hi @carlosbort and welcome to the Mattermost forums!

Thanks for letting us know, the underlying problem has already been adressed and should be fixed with the 5.3 appstore release, so you could try to switch back then once the new version has been released (unless it’s OK for you to keep using the DMG/non-appstore version).