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What is File Locking?

File Locking is a protective background process that prevents users from accidentally overwriting each others work in a shared storage environment.

File locking occurs on many types of network storage systems including ProMAX Platform servers and cannot be disabled.

How does it work?

File locking works by tracking each file that network users access, and when a previously unused file is opened, it assigns a temporary write-lock to the user who opens that file first. While that user is accessing the file, they are the only one that can write (and save changes) to that file and its associated folder path. Other users may access that file, however they will be granted read only access. If the primary user closes access to that file, the next user who opens the file is granted the write lock. While only one user can write to the file at any one time, any number of users can read from the same file simultaneously.

How does this affect me?

In most Post-Production environments, this does not affect users as each user is typically writing to a single file, their NLE or graphics project file.

For example, in an environment with 10 premiere users working on individual projects, all sharing the same batch of raw media, file locking would be applied like this:

  • Each user would open their own unique project file and be granted a write-lock on their respective project files.
  • Because Premiere references the raw media in its projects, the first user to open their project would also open all of the raw media files linked in that premiere project and be granted write-lock on that media.
  • The remaining 9 users would open their premiere project and be granted read-only access to the associated raw media.
  • All editors would be able to edit successfully as they are only making and saving changes to their unique project file (which they each have a write-lock on). No changes are being made to the associated raw media, they are all successfully reading from it as necessary.

File Path Changes

One aspect of File Locking that can cause disruption if not properly understood is the locking of file paths. When a file is write-locked open, some environments (OSX/MacOS in particular) will lock open the entire file path of a file to protect it from being moved/deleted by another use while it's in use.

This means if a user opens the file "/Project-Alpha/NLE_files/CUT A/My_premiere_project.prj", that entire folder path will be protected against anyone else changing it.

As an example, this can result in confusion if a second user is tasked with changing the name of "Project-Alpha" to "Project-Alpha 1". Because there is a file in use by the first user in the "Project-Alpha" folder path, that entire path is protected from change until the first user releases the file. Until then, the "Project-Alpha" folder cannot be renamed, deleted, or moved as it would break the pathing to the file in use.

How to identify File-locking issues in your workgroup

If you or your users are reporting that they cannot save a file, or edit/move/delete a folder on a Platform Space where they have full read and write access, they are likely being prevented from doing so by files and/or folder paths being locked open by other users.

Some programs react differently when trying to write to a file that is write-locked by another user. Here are some common behaviors that may indicate file locking is in play:

  • When saving a file, a user is given a "You don't have permission to that file" message, even though they've been able to write to it before.
  • When attempting to save a file or make a change a folder on OSX/MacOS the user is asked to enter their administrator credentials, and when they do, nothing happens or they are given a "You don't have permission to that file/folder" message.
  • A generic error upon trying to "save", but a "save as" works fine if you rename the file.

File Locking in MacOS

MacOS functions in a way where it's possible for a single user to lock files open on their own workstation, even if no one else is using the network system. This occurs because each individual instance of a program running in a MacOS may lock a file or folder paths open independently of each other. This can result in confusing moments where finder may lock open a folder path because the entire path and contents are being displayed in list view. Also common is when a user uses finder to open a project file, such as a photoshop .psd file. Because finder often displays a small preview of the psd file in the finder window, if the user attempts to save that psd file, they'll find they're locked out of it because that finder window preview has a hold on the file. To minimize this, we recommend that users operate finder in Icon view, without file preview turned on when attempting to rename folder paths, and to ensure that no other program on the system (such as an open premiere project or another finder window) has any files or folders in that same path open at the time.