Dr Bainbridge's suggested bugfix worked: when incremental-building on windows, deleting items when the collection had a longer filename like manifest-demo-e failed with warnings from gdbm_delete about item for filepath as delete key not being found. Deleting worked in collections with shorter filenames (ultimately, full path to files being deleted were shorter). As Dr Bainbridge suggested, it merely required ensure that we compare fll/long filenames with what's in the database, as windows shortfilenames won't hit a match. Fix is a call to util::upgrade_if_dos_filename() to ensure we compare apples with apples. Tested on Windows binary GS2 installation and it worked, but copied the line to linux GS2 install as it's an SVNinstall and will allow me to commit.