If you only have 12 rooms and only 5 are allowed in the wasteland than the game shouldn't allow you to open more if you are at the maximum limit of space for them.i didn't realize there was a limit for the wasteland. Now I have two my handies outside my vault and nowhere to go. Or at least be able to put them in storage.

How many levels of vaults you have?

Try build an elevator for a new level to accomodate one more.

I have 13 levels and 20 Mr handies. 5 of them are in the wasteland. I didn't realize there was a limit for the wasteland