Delete Sweep Error - "Base sketch for roof is invalid"

[slmaher]

Why do I sometimes get the error message "Base sketch for roof is invalid" when I try to delete or change a curb and gutter sweep?

[Mr Spot]

Sounds like your using an old version and have used the massing tool? Is this the case?

Using the massing tool used to automatically create roofs, floors walls etc depending on the mass...