Nicknames, Skins & Accounts 63,771 views
How to Fix 'Username Contains Invalid Characters' Error (Minecraft 1.21.1 on macos-arm64)
Detailed guide on how to fix 'username contains invalid characters' error in Minecraft 1.21.1 for macos-arm64.
Compatibility:OS: macos-arm64•Loaders: All•Versions: 1.21.1
nicknamefix-disallowed-characters-error1-21-1macos-arm64
Causes of Error & Description
Overview & Technical Requirements Comprehensive instructions for how to fix 'username contains invalid characters' error on Minecraft 1.21.1 running under macos-arm64.
Step-by-Step Instructions 1. **Open Account Switcher**: In SuperLauncher on macos-arm64, click the account avatar in the top-right corner and select 'Manage Profiles'. 2. **Configure Username & UUID**: Enter your desired nickname following valid alphanumeric rules for Minecraft 1.21.1. Ensure no forbidden symbols are used. 3. **Preserve Playerdata & World State**: Check the local world saves directory to link existing NBT playerdata files if migrating between usernames.
Troubleshooting & Common Pitfalls Offline nicknames generate consistent UUID v3 values based on username MD5 hashes. Modifying names may reset local achievement badges and ender chest inventories.
Step-by-Step Solutions
How to Fix 'Username Contains Invalid Characters' Error
Automated Fix1
Open Account Switcher
In SuperLauncher on macos-arm64, click the account avatar in the top-right corner and select 'Manage Profiles'.
superlauncher://account/offline2
Configure Username & UUID
Enter your desired nickname following valid alphanumeric rules for Minecraft 1.21.1. Ensure no forbidden symbols are used.
3
Preserve Playerdata & World State
Check the local world saves directory to link existing NBT playerdata files if migrating between usernames.
Quick Repair in SuperLauncher
Execute action without manual configuration "setup_nickname"
Did this article solve your problem?
Your feedback helps improve our guides and launcher algorithms.
SuperLauncher
Жива підтримка
👤 Чат з оператором
Напиши повідомлення — оператор побачить його одразу і відповість тут же в чаті.