Dropbox does not upload your whole Truecrypt volume every time you change it. It just uploads the blocks that are changed. It's pretty efficient. The real prob

Dropbox does not upload your whole Truecrypt volume every time you change it. It just uploads the blocks that are changed. It's pretty efficient. The real problem with using a Truecrypt volume on Dropbox is concurrent changes to the same volume. It happens if you mount the Truecrypt volume on 2 machines at the same time. It will mess up badly.