Cloud storage service Dropbox has blocked access to Boxopus, a service that let people download files through BitTorrent directly to their Dropbox folders. After being featured on TorrentFreak and other sites late last week, Boxopus says it received the following message from a Dropbox engineer:

It’s come to our attention that latest Boxopus features could be perceived as encouraging users to violate copyright using Dropbox. Violating copyright is against our terms of service, so we are terminating your app’s API access. Once your access is revoked, any API calls your app makes will fail.

At this point, the Boxopus site is still up, but attempting to sign in with Dropbox leads to a "page not found" error and the company says its connection to the service has been severed. Boxopus, meanwhile, claims this is a new development. The founder tells TorrentFreak that Dropbox explicitly approved an alpha build of Boxopus a few weeks ago, and that "once the alpha version was approved we were pretty sure that Dropbox was okay with it." It's not clear to what "latest features" the message refers.

If Dropbox did approve an early build of Boxopus, this ban is definitely a painful loss for the startup. It's not, however, too surprising. Dropbox has been used as a point of comparison by file-sharing services like RapidShare, but it's worked hard to remove any appearance of impropriety and block links to files it finds infringe copyright. It should still be possible to download torrents to Dropbox through other means, but it looks like the company didn't want to be associated with something that's seen as legally dubious, even if it has significant non-infringing uses.