There are a few possible reasons for the "Other Users" category to take up space on your MacBook, even if you don't have any other user accounts:
1. System files: Some system files and temporary files are not associated with any user account and are classified as "Other."
2. Cache files: Applications can create cache files that aren't associated with any user account.
3. Time Machine backups: If you have Time Machine enabled, it may be creating backups that are classified as "Other."
4. Leftover files from a previous installation: If your MacBook was restored from an old MacBook, there may be leftover files from the previous installation taking up space.
To reclaim space, you can try the following:
1. Use a disk space analyzer tool to identify what types of files are taking up space in the "Other Users" category. DaisyDisk and GrandPerspective are popular options.
3. Disable Time Machine backups or adjust the settings to limit the amount of space it can use.
4. Check for leftover files from the previous installation and delete them if they're no longer needed.
It's always a good idea to make sure you have a backup of your important files before making any changes to your system.
[Edited by Moderator]