I have lost my user library folder

Changing your short user name on macOS is generally discouraged due to the potential for system corruption and data loss. It's a complex process that can cause issues if not done carefully, and it's often better to create a new user account or use the old name if possible. 

Here's why it's risky:

• System Corruption:
• Changing the short user name can lead to a corrupted system file, making it difficult or impossible to log in. 
• Data Loss:
• Files and settings associated with the old username might not be automatically transferred to the new name, potentially leading to data loss. 
• Troubleshooting:
• If something goes wrong, troubleshooting can be difficult, as the system may not recognize the new name. 
• Admin Privileges:
• Changing the short name can sometimes cause the account to lose its administrator privileges, requiring a second administrator account to fix. 
• Third-party Software:
• Some third-party applications might be configured to use the old user name and could malfunction if it's changed. 
• Home Directory Confusion:
• If the home directory is also renamed, it could lead to confusion about where data is stored, potentially causing issues with software that expects the old path. 

In short, it's best to avoid changing the short user name on macOS unless you have a very good reason to do so and are willing to take the time and effort to do it correctly. 

What you should do instead:

• Back up your data:
• Before making any changes, back up all your important files and folders. 
• Consider creating a new user:
• If you want to change the username, it's generally safer to create a new user account with the new name and then move your data to the new account. 
• Use a second administrator account:
• If you do decide to change the short name, make sure you have a second administrator account available in case something goes wrong. 
• Consult Apple Support:
• If you're unsure about how to change the short name, consult Apple Support for guidance. 

oops3point0 wrote:

I was trying to change my username and seem to have screwed that up. I have a MacBook Pro 2024.

you can restore your user from one of your backups...

ref: Change the name of your macOS user account and home ..