STATUS_TOO_MANY_NAMES 0XC00000CD — Fix in 3 Steps

What's actually happening here

This error fires when the NetBIOS name table on your network adapter hits its limit — default is 17 entries on Windows. Each entry is a name your computer broadcasts so other machines on the LAN can find it. You'll see this when joining a domain, sharing folders, or running apps that register lots of NetBIOS names (like SQL Server, Hyper-V, or old backup software). The trigger: 17 names are already taken, and something tries to add one more. Windows throws STATUS_TOO_MANY_NAMES (0XC00000CD) and the operation fails.

Three fixes below. Start with step 1 — you can do it in 30 seconds. Move down only if the problem comes back.

Fix 1: Flush the NetBIOS cache (30 seconds)

This clears stale names — old broadcast registrations that never got cleaned up. Open Command Prompt as administrator and run:

nbtstat -R

The capital -R switch purges the remote name cache and reloads the Lmhosts file. It doesn't clear the local name table, but it often frees a slot or two because Windows re-requests names lazily. After running it, try the failing operation again.

If that didn't help, also run:

ipconfig /flushdns

Not directly related — DNS is not NetBIOS — but DNS and NetBIOS interact badly on some older network stacks. A flush costs nothing and might clear a secondary lock.

Fix 2: Reduce NetBIOS name pollution (5 minutes)

Something is registering too many names. Likely suspects:

• Multiple network shares with different names (check net share in cmd)
• SQL Server or other server software registering NetBIOS aliases
• Hyper-V virtual switches creating extra names
• Old printer or scanner management software

To see your current name table:

nbtstat -n

This lists every NetBIOS name your computer has registered. Count them. If you're at 16 or 17, you're full. The output shows the type code — <00> for workstation, <20> for server, <03> for messenger service. The blue screen or event log entry around the 0XC00000CD error usually tells you which app failed. Kill or reconfigure that app.

One common cause: having NetBIOS over TCP/IP enabled on multiple adapters (Wi-Fi + Ethernet + Bluetooth). Disable it on adapters you don't use for file sharing:

1. Open Network Connections (ncpa.cpl)
2. Right-click the adapter → Properties
3. Select Internet Protocol Version 4 (TCP/IPv4) → Properties → Advanced
4. Go to the WINS tab
5. Select Disable NetBIOS over TCP/IP

Do this for adapters that don't need file sharing (VPN adapters, Hyper-V virtual adapters, Bluetooth PAN). Leave it enabled on your primary LAN adapter.

Fix 3: Increase the NetBIOS name table limit (15+ minutes)

This is the nuclear option. Only do this if you've confirmed step 2 doesn't help — meaning you genuinely need 18+ names on one adapter. The default limit is 17. Microsoft docs say you can bump it via a registry value that doesn't exist by default.

Back up your registry first. One wrong key and you're reinstalling.

1. Open Regedit as administrator
2. Go to:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NetBT\Parameters
3. If it doesn't exist, create a new DWORD (32-bit) value named:
   SizeOfNameTable
4. Set the value data to a decimal number. I use 34 — double the default. Some guides recommend 255, but that's overkill and can cause broadcast storms on large subnets. 34 gives you room for two full sets of names (workstation + server + messenger + browser + additional shares).
5. Click OK and close Regedit
6. Reboot the machine

The reason this works: NetBT (NetBIOS over TCP/IP) allocates a fixed-size table when the adapter initializes. SizeOfNameTable tells the driver how many entries to reserve. Without this key, it uses 17. With it, you get whatever number you set. Windows will not dynamically expand the table — it's a compile-time constant in the driver, tweaked by this registry parameter.

Side effect to watch for: A larger table means more broadcast traffic on your local subnet. If you have dozens of machines all with 100+ names, your network might get chatty. For a single desktop or server, 34 is fine.

When to give up and call in the pros

If after all three fixes the error still pops up every few hours, you might have a driver issue. Update your network adapter driver from the manufacturer's site — not Windows Update. Realtek and Broadcom drivers have known bugs where they don't properly release NetBIOS names on adapter reset. A clean driver install sometimes fixes it without touching the registry at all.

One last thought: if you're on a corporate domain with aggressive Group Policies, your IT team may have set a custom name limit via a startup script or a different registry location. Check with them before bumping SizeOfNameTable — they might have a good reason for keeping it low.