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ERROR_INVALID_COMPUTERNAME
The specified computer name has an invalid format.
ERROR_INVALID_COMPUTERNAME has decimal value 1210 (0x4BA). Windows rejected the name before it could complete a lookup, join, rename, or network-management operation. The failure concerns syntax and naming context, not proof that the computer is offline.
Determine which form the API expects
A Windows computer can be represented by a NetBIOS name, DNS host name, fully qualified DNS name, UNC server component, or directory account name. Some APIs accept only one of these forms. A leading \, a trailing dot, an embedded DNS suffix, or a domain prefix may be correct in one parameter and invalid in another.
Input checks
- capture the unmodified UTF-16 value and character count
- detect leading or trailing whitespace and nonprinting characters
- separate host name from DNS suffix instead of concatenating blindly
- verify label length, total length, and allowed character rules for the target namespace
- check whether the API expects the local computer to be represented by
NULLrather than its name
Use the platform validator when available
For domain join and rename workflows, NetValidateName can validate names for a specified account or computer-name type. Validation should use the same target domain or server context as the eventual operation because uniqueness and policy checks can depend on directory state.
Do not confuse formatting with reachability
If the name is syntactically valid but cannot be resolved, expect DNS, NetBIOS, RPC, or network errors instead. Error 1210 should lead first to parameter inspection. Pinging a malformed string or changing firewall rules does not address the returned condition.
Provisioning recommendations
- generate a canonical short computer name before constructing an FQDN
- store the chosen name separately from display labels and asset descriptions
- validate before rebooting into a rename or domain-join sequence
- log old name, proposed name, domain target, and validation result
- handle duplicate-name errors separately from invalid-format errors
Example
A deployment script passes HOST01.example.com to a parameter that expects the short computer name. The operation returns 1210 even though DNS resolves the FQDN. The script validates and supplies HOST01 as the computer name while keeping the DNS suffix in its dedicated configuration field.
References
- Microsoft: System Error Codes (1000–1299)
- Microsoft: NetValidateName function
- Microsoft: Naming conventions for computer and domain names
- Microsoft: Naming conventions
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