The Global Catalog is your Active Directory’s search engine—without it, logins fail, lookups return nothing, and applications struggle to find user info.
No reachable domain controller is acting as a global catalog. The users may experience:
Run the following command as an administrator:
Step 1. Check for an available GC by running the following Command Prompt command:
Step 2. Enable GC on a domain controller if missing:
Step 3. Force replication by running the following Command Prompt command:
Global Catalog is not available for universal group membership lookup during login.
Step 1. Ensure the user’s logon domain controller is also a global catalog or can reach one by running the following Command Prompt command:
Step 2. Assign a domain controller as a global catalog if there isn't one.
Directory search or query fails due to no global catalog is available.
Step 1. Confirm global catalog SRV record in DNS.
Step 2. In DNS Manager, check under _gc._tcp.yourdomain.com.
Step 3. If missing, restart the Netlogon service by running these Command Prompt commands:
Step 4. Re-register DNS by running the following Command Prompt command:
GC unreachable due to DNS misconfiguration or replication failure.
Step 1. Check DNS SRV records by looking for the following:
Step 2. Verify replication by running the following command in the Command Prompt:
