A hosted storage system receives a request from a requester to access a hosted resource. The hosted resource includes a binary large object. The hosted storage system providing hosted storage to a plurality of clients that are coupled to the hosted storage system. A copy of the hosted resource is created. A copy message including the copy of the hosted resource is provided to the requester. The hosted resource is maintained in the hosted storage system while the requester modifies the copy of the hosted resource. A message is received from the requester. The messages include a modified copy of the hosted resource. It is determined that the hosted resource has not been modified since the copy of the hosted resource was created. The hosted resource is replaced with the modified copy of the hosted resource.