> For the complete documentation index, see [llms.txt](https://janelia-flyem.gitbook.io/neutu/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://janelia-flyem.gitbook.io/neutu/body-proofreading/intro-to-locking-bodies.md).

# Body Lock

{% hint style="info" %}
This function needs the [Librarian](https://github.com/janelia-flyem/librarian) service to work.
{% endhint %}

Users can collaborate by simultaneously editing the database instead of working separately.  Although this strategy saves time, conflicts may occur when two or more users try to edit the same body.  To manage this conflict, NeuTu “locks” bodies under certain circumstances, so only one user can make and save changes to the body at a time.  Once the changes are uploaded to the server, the body is automatically unlocked and another user can edit it!  

When changes are saved to the server, any updates from other users are automatically refreshed. If a user tries to work on a locked body, NeuTu issues a warning and the user can not work on the body until it is unlocked.   

![Warning message for trying to split a locked body](https://2926737796-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-Ld57Fj27nUB-NnjPb7c%2F-LzES7iqQ55WvEtJ_w2c%2F-LzEUDq8VyXqiM7ldPlP%2Fimage.png?alt=media\&token=ab3b4933-466b-403a-8cbc-49fa2d72543b)

NeuTu locks a body whenever the user makes changes to body by merging or splitting. NeuTu does not lock bodies that have been selected for viewing, so multiple users can view the same body at the same time!