You have problem which looks like this on picture below and nobody from shelter can't interact with this facility? This guide is for you.

Saves are located in

BACKUP YOUR SAVES BEFORE EDITING!

Using this tool decrypt your save:
https://gtm.steamproxy.vip/app/1289380/discussions/0/3274690571075140864/

After decrypting you can edit your save in text editor like Notepad or Notepad++

If you can't upgrade your Oxygen Filter, find:

If you can't upgrade your Water Collector, find:

If you can't upgrade your Water Purifier, find:

If you can't upgrade your Weather Vane, find:

Bugged section for Oxygen Filter will look like(upgrade name between recipeID tags obviously may be different):

Fixing procedure for other facilities is the same. Just remove upgrade name and that's all. You fixed it! Now it should look like:

Of course, by doing so, you lose the materials used to start this improvement. Sorry but I can't refund them.

Now you can move your fixed and encrypted save to the place from where you took it and remember to save it under the same name as it was at the beginning.

Avoid saving game or loading autosaves when upgrading these facilities. In my opinion this can cause this problem.

I already test this method on several saves with this problem which I found on official Sheltered 2 discord https://gtm.steamproxy.vip/app/1289380/discussions/0/3119297977951530690/

If you tried to fix your save but still have problem, you can find me on this official discord under the same nickname and send me your save. I can try to fix it.