Thought I would post this here for anyone interested. Once you complete 5 missions after finishing Horizon, you get a message from the Elusive Man which triggers the Collector Ship mission. Once this happens and you get the message that the Elusive Man wants to talk with you, the galaxy map is locked out.
Keep in mind, if you have already completed 5 missions and the elusive man "Wants to speak with you" about the collector ship mission, then this won't work. In my case I had completed only 4 missions after Horizon and it worked fine.
First, download Gibbed Save Game Editor for ME2:
LinkBe sure to make a backup copy of your saved games
before editing any save games with the editor.
Open the editor, open the desired save game file via the editor ((\My documents\BioWare\Mass Effect 2\Save\))
In the editor, go to Plot tab, then Henchmen tab, then Flags tab. Look for the box marked "Jacob in alternate appearance". It should be unchecked. Check/enable that box then save the save game file via the editor.
Once this is done you can load up the save game you edited. Now that it has been modified, the
elusive man collector ship mission prompt will NOT come until, at some point later, you go back into the save file via the editor and uncheck "Jacob in alternate appearance". Once you uncheck it and load up the save game the Collector ship prompt will be there waiting for you and the galaxy map will once again be temporarily locked out.
PLEASE NOTE: This is a one time only thing so far as I have tested. If you attempt to repeat this process a second time the galaxy map will lock up and that particular save game is screwed.
This edit did allow me to go complete all side missions, recruitment missions and loyalty missions, and THEN do the collector ship mission. Enjoy.