Steam says updating but does nothing
That’s exactly what this article is here to discuss. It is FSX plus the Acceleration add-on, which includes Service Pack 2, so if you’re currently successfully running FSX, surely you won’t get anything from buying this, right?
Things aren’t where they were and file versions, sizes and dates have changed, so that can cause problems.
On the other hand, and this is critical, most things with FSX: SE.
What stops most of them working immediately is not the code changes, but rather the executable installers for those add-ons.
Just point it to the right place and subject to the limitations mentioned above, it will almost certainly work.
The link at the end of the section above proves the point nicely, but if you check the developers’ forums for the add-ons you want to install, you’ll probably find advice on how to get their add-on working.