When a file is locked by one developer it cannot be edited by another developer. If your administrator has disabled multiple checkout then whenever you checkout a file it will be automatically locked. The PureCM administrator can also configure certain files to automatically lock when checked out. This can be useful for files which cannot be merged, e.g. binary files.
A locked file has a different icon to show that the file cannot be edited by you. This is described in the section called “File Icons”.
Sometimes you may want to manually lock a file. For example, you may want to restructure the whole file which would make merging someone else's change difficult. In these situations you can right-click the checked out file and select the 'All Tasks | Lock' menu.
The locks will automatically be released when you submit your changes or if you revert your changes. You can manually release a lock by right-clicking the locked checked out file and selecting 'All Tasks | Unlock'.