Over the last few days we have seen several comments from players in the FSX: Steam Edition community stating that they have experienced unexpected errors when trying to host a multiplayer session. We looked into these reports and would like to thank everyone who has taken the time to get in touch with us regarding this matter.
The cause of this issue was an update that Valve released for the Steam desktop client on the 9th of April. Yesterday Valve confirmed this stating that the update could cause a “crash which affected dedicated servers for some multi-player games”. They have now released a second update which corrects these crashes and installing it is expected to return multiplayer functionality in FSX: Steam Edition to normal.
The update will automatically download and install through Steam however you may need to restart your Steam client if this is not happening for you. The full changelog for the update can be found here on the Steam website
Thank you for your patience,
Microsoft Flight Simulator X: Steam Edition Team
Dovetail Games