This post discuss the absence of a multi-host distributed file locking mechanism within Windows, and specifically within folders replicated by DFSR. Distributed File Locking refers to the concept of having multiple copies of a file on several computers and when one file is opened for writing, all other copies are locked. This prevents a file from being modified on multiple servers at the same time by several users. Distributed File System Replication (DFSR) operates in a multi-master, state-based design. In state-based replication, each server in the multi-master system applies updates to its replica as they arrive, without exchanging log files (it instead uses version vectors to maintain “up-to-dateness” information). No one server is ever arbitrarily authoritative after initial sync, so it is highly available and very flexible on various network topologies.