@alk said in Mac OS X Management Console Installation Error:
Could you please try this version: https://www.dropbox.com/s/wmwq997zlny55nk/nxmc-1.2.10.dmg?
This build is signed with proper keys from Apple, so it should work properly with Gatekeeper enabled.
Please note: it's built from from latest sources and incompatible with 1.2.9, so don't overwrite your existing app.
I can confirm that this version starts without any issues when the setting for "Allow apps downloaded from" is set to: "Mac App store and identified developers" under Security & Privacy.