Which character is not allowed in user account names?

When establishing user account names, especially within systems like Active Directory, a specific set of characters is prohibited due to their reserved meaning in system operations, scripting, or file path conventions. These characters can cause conflicts or unexpected behavior if used in an account name.

Characters Not Permitted in User Account Names

The following characters are not allowed in user account names:

Why Are These Characters Restricted?

These characters are typically restricted because they hold special significance in various computing contexts. For instance:

• Path Delimiters: / and \ are used to separate directories in file paths.
• Wildcards: * and ? are commonly used as wildcards in search patterns.
• Command Separators/Redirection: ; and | are used to separate commands or redirect output in command-line interfaces.
• Special Operators: = often signifies assignment, while < and > are used for input/output redirection.
• Reserved for Special Purposes: Characters like " and [/] might be used for quoting strings or indicating arrays/collections in programming or scripting.

Using these characters in a user account name could interfere with system functionality, lead to security vulnerabilities, or prevent proper resolution of the account.

Permitted Characters and Naming Best Practices

Conversely, many other special characters are generally permitted in user account names. These often include:

• Spaces
• Periods (.)
• Dashes (-)
• Underscores (_)

While spaces are technically allowed, it is widely considered a best practice to avoid them in user account names. Spaces can complicate scripting, command-line operations, and URL encoding, potentially requiring names to be enclosed in quotes or otherwise handled specially.

General Naming Guidelines:

To ensure robust and manageable user accounts, consider the following best practices:

• Keep it simple: Use alphanumeric characters, periods, dashes, and underscores.
• Avoid spaces: Opt for periods or underscores as separators if needed (e.g., john.doe or john_doe).
• Maintain consistency: Establish a clear naming convention for all user accounts (e.g., firstname.lastname, firstinitiallastname).
• Limit length: While many systems support long names, shorter, memorable names are often more practical.

Adhering to these guidelines helps create user account names that are easy to manage, compatible across different systems, and less prone to causing unexpected errors.