Unchecking the box for "I sold or otherwise disposed of this rental in 2017" is not anywhere near enough to "undo" the sale. You have to work through each individual asset in the assets/depreciation section, work it through "as is" by indicating YES I STOPPED USING THIS ASSET IN 2017 and change all the sale amounts to zero. Then you have to work through each asset again, and select NO I DID NOT STOP USING THIS ASSET IN 2017.
If a vehicle was involved with then rental, then you have to work through the vehicle expenses section too, just like you did the assets/depreciation section.