Is the build tab removed from all your workspaces or just your current workspace? In either case there are several versions of the Build panel. The different flavors of the build panel are: Build - ACA, Build - Electrical, Build - HVAC, Build - Piping, Build - Plumbing, and Build - Schematic. To restore a panel to a workspace ribbon tab you will need to start the CUI editor and under Ribbon Tabs you will need to find the version of the Home panel that is in your current workspace. If it is the Home - HVAC Tab then you will need to expand the Panels section and drop and drag the Build - HVAC Panel up to the Home - HVAC Tab.
You didnt mention which workspace you were working in but it is entirely possible that it is a custom workspace. If that is the case then you will need to chose which build panel you would like to insert or you could customize your own with all of your most commonly used commands.
![Autodesk Design & Make Report](https://forums.autodesk.com/t5/image/serverpage/image-id/1350519iCB55845EBFC43016/image-size/large?v=v2&px=999" "Autodesk Design & Make Report")
