What triggers a rebuild of the same revision is presence of build_requested file in #{CRUISE_DATA_ROOT}/projects/#{
project.name} directory.
If you would like to debug it, start from Project#build_necessary? and see why does it keep returning true. This file s supposed to be deleted in the beginning of Project#build_if_necessary, and the implementation is using rm_f. So, I suspect that this file is not removable on your computer.
> something in the code assumes your cruise data folder is on the C drive.
Could you give some more specific details? This sounds like something worth fixing.
--Alex