Thanks for the great feedback on Update 20. An update 20 Hot Fix is now available which fixes up several reported issues. 

Release Notes

• Item chests are now set as avoid tiles instead of unwalkable
• Fixed: Some colonists unable to perform any jobs when loading a saved game created in Update 19
• Fixed (Mac): Main menu buttons not functioning
• Fixed: Colonists not crafting anything if unable to reach required materials for one of the queued craft recipes.
• Fixed: Colonist not constructing if unable to collect all items for first object in construction queue.