File locks are used to restrict access to computer files, to prevent reading of the file while it's being modified or deleted.

File locks only work when a single controller, or gatekeeper, exists to manage the lock. File locking across networked or shared systems is not consistently implemented, meaning that there will be parties that remain unaware of a lock's existence.

Mainframes and Windows based operating systems provide built-in methods for file locks whereas Unix, Linux, and MacOS based operating systems do not.

Applications and scripts may also implement their own file locking methods but other applications, scripts, and systems will be unaware of these proprietary file locks. Use of proprietary methods can be detected by the existence of lock files.

The Files.com platform has access only to its own internal file locks and locks that are explicitly published by a remote server or its connection protocol. This means that file locks on remote servers may not be viewable by Files.com.

For example, a locked file on a Windows based remote server cannot be synced as the operating system will prevent the file from being read or overwritten while it is being modified. However, a file on a Linux based remote server can be synced, even though it is currently being modified, causing invalid or partial data to be synced.

As a best practice, open files (those that are in the process of being updated or modified) should never be included in the source or destination of a Remote Sync.