A simple program (see https://gist.github.com/mchapman/078818d5229129c8cce5) inserts a document into an empty file and does a find. In 2.4 the document is found, and in 2.6 it isn't, but in the shell the behaviour is the same in 2.4 and 2.6, so I am thinking the error is either in Mongoose or the Node driver. I am reporting it here as this seems to have more traffic than the Mongoose equivalent...