FINALLY!
Can't eFile due to C 27b shows "0"? Must be blank, no 0. Can't delete in Forms either, so:
Go to step by step,
Business> Choose what I want to work on
Business income and expenses> update
Choose your business> edit
Business Expenses> Other common business expenses> update
Energy Efficient building> update
here you can finally backspace or delete the "0" This must be blank, no numbers at all or you cannot eFile