Hello.
If you are using an older save from before the new 3.0.1 update they may not function correctly.
When you start the game with the new version there should be a popup describing how to roll back to a previous game version if you wish to continue on an older save.
" Please note that save file compatibility between versions is not guaranteed. If you have an important 2.8.1 game going, please roll back to that version before trying to load the save in 3.0.1. You can roll back to a prior version via right click on Stellaris in library -> Properties -> Betas -> choose the desired version. "
If you are using an older save from before the new 3.0.1 update they may not function correctly.
When you start the game with the new version there should be a popup describing how to roll back to a previous game version if you wish to continue on an older save.
" Please note that save file compatibility between versions is not guaranteed. If you have an important 2.8.1 game going, please roll back to that version before trying to load the save in 3.0.1. You can roll back to a prior version via right click on Stellaris in library -> Properties -> Betas -> choose the desired version. "