I have 500 unemployed workers and a lot of buildings that need workers, when I tried to manually hire them it doesn't work and they wont do it on their own.
I have the same problem. I'm playing my second colony and during both have had to build hundreds of Water wells since all my Athmospere condensers all the sudden had no workers and apparently the colonist just didn't feel like working. Or then it's a bug.
https://www.ape-apps.com/viewpage.php?p=4018
https://www.ape-apps.com/viewpage.php?p=2010
check those two they are talking about unemployment problems already ^^
https://www.my-colony.com/colonies/dNDgEef6/
https://www.my-colony.com/colonies/4GLdZllJ/
When my workers will not work, i lower their salaries and tax them to kingdom come. That wil get them off their lazy asses :D