I finally found the problem in my situation. I am using a mod called Global AI Ship Traffic mod (gaist) from flightsim.to simulate shipping traffic. I didn’t realize that an update changed (and substantially added more) data for the shipping route. This is enough data to hang MSFS when loading a flight unless you have a very powerful computer. The developer recognizes this and split up the gaist files into separate routes for different regions in the world, which I tried and solves that loading problem. A newer version of gaist is being worked on that will dynamically query shipping data so it doesn’t all have to be loaded at start.
So if you use the Global AI Ship Traffic mod you can try the following fixes:
- disable the mod to confirm it’s causing the hang
- look at the workaround mentioned in the avsim forums.
- or wait for a future version of gaist.
Hope this helps. Unfortunately, it is likely that there are many different old mods that may cause a hang. I had to wipe everything out and start from scratch to get my system working again. Other things to try (probably mentioned elsewhere, but here goes):
- Use MSFS Addons Linker.
- Try cleaning out your state-saving folder in case it has incompatible state with existing or updated mods. You may find plane data in any of the “Packages” folders mentioned in the MSFS support article here.