Windows 11 introduced the ability to customize the default user profile folder name during setup with the May 2026 Optional Update KB5089573. Previously, the folder name was automatically truncated to the first five letters of the user's email ID used for logging in. The default user folder is located under C:Users and serves as the primary directory for personal files. Users can now choose a custom name for their user folder during the Device Name page in Windows setup, but if skipped, the default name will be used. Custom user folder names must adhere to standard Windows naming requirements and cannot include reserved characters or system names. The feature is being rolled out gradually, and existing users may need to reinstall Windows to change their folder names.