The Files tab on the Vault Settings dialog box contains options for enforcing unique file names.
By default, unique file names are not enforced in the vault database. The only restriction is that two files with the same name cannot exist in the same folder. With unique file names enforced, files in the vault must each have a unique, identifying name. This rule is enforced when files are added to the vault, renamed in the vault, or restored to the vault. If unique file names are going to be enforced, it is recommended that this option be set before any files are added to the vault, though it can be turned on at any time. Using Find Duplicates, you can locate duplicate file names in the vault to help resolve any file name conflicts before turning on this option.
Enforce Unique File Names
As a best practice, do not enforce unique file names if any files with duplicate names are checked out. If unique file names are enforced while a duplicate file name is checked out, the setting can be temporarily turned off to allow the file to be check back in, or the vault user can undo the check out, and then rename the file before checking it back into the vault.