RDP Error 0XC00A0034: License In Use – Real Fix

You're trying to RDP into a Windows Server — maybe Windows Server 2019 or 2022 — and instead of getting a desktop, you get a popup that says: "Your request to connect to this terminal server has been rejected. The exact error code is: 0XC00A0034." The full error text might also say STATUS_CTX_CLIENT_LICENSE_IN_USE.

I've seen this most often on servers where someone didn't properly log off — they just closed the RDP window, leaving a disconnected session. That session holds a license hostage. On servers with a limited number of CALs (Client Access Licenses), the pool runs dry, and your new connection gets kicked back. Could also happen if you've got a stale license cache on the client machine.

The root cause is simple: the terminal server thinks all available licenses are taken. It doesn't matter if those licenses are actually being used — if a session is disconnected but not logged off, the license stays checked out. The quickest fix is to clear that session. But if you can't even get in, we need another path.

Fix 1: Kill Stale Sessions from Another Admin Connection

If you can RDP into the server with a different admin account (or if there's a local console session), do this:

1. Open Server Manager. Go to Remote Desktop Services > Collections (or just Sessions in older Windows Server versions).
2. Look for sessions in a Disconnected state. Right-click and choose Log Off. Wait for the session to close.
3. Try your RDP connection again. If there's a free license, it should let you in.

But here's the thing: sometimes you can't even get a second admin session. Maybe the server only has two admin RDP slots and they're both stuck. In that case, move to Fix 2.

Fix 2: Reset the License Grace Period (No Admin Login Needed)

This works when you've got physical or iLO/iDRAC access to the server — or you can boot it into Safe Mode.

1. Restart the server and press F8 during boot to enter Safe Mode with Networking.
2. Log in as a local admin. The RDP license check is bypassed in Safe Mode.
3. Open Command Prompt as Administrator. Run:
   net stop TermService
   Wait for it to stop.
4. Delete the license cache folder. Run:
   del /q /s C:\Windows\System32\RDP\LicenseCache\*.*
   Note: the exact path might be C:\Windows\System32\Microsoft-TerminalServerClient\ on older systems. Check both.
5. Restart the server normally. The license cache is rebuilt fresh on next RDP login.

Fix 3: Clear the Client License Cache (Your Machine)

Sometimes the problem is on your end — your Windows 10 or 11 client has a corrupt or stale license token that the server rejects.

1. Close any open RDP sessions.
2. Press Win + R, type regedit, and hit Enter.
3. Navigate to:
   HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\MSLicensing
4. Right-click the MSLicensing key and choose Export (just in case). Then delete the entire MSLicensing key.
5. Close Regedit. No reboot needed — next RDP connection will recreate the key with a fresh license.

If It Still Fails

You might be out of actual CALs. Check the Remote Desktop Licensing Manager (licmgr.exe) on the server. If it shows zero available licenses, you need to buy more or, in a pinch, temporarily reset the grace period via:

reg add "HKLM\SYSTEM\CurrentControlSet\Control\Terminal Server\RCM" /v GracePeriod /t REG_BINARY /d 010000000000000000000000000000000000000000000000 /f

But that only buys you 120 days — Microsoft's not stupid, and neither should you be. Buy the CALs.

Real scenario: Last month I had a client with 10 users hitting a 5-CAL server. Their accounting department kept their RDP sessions open overnight. One logoff command fixed it, but they needed more CALs anyway.

Start with Fix 3 — it's the fastest. If that doesn't work, go to Fix 1. If you're locked out entirely, Fix 2 is your lifeline. You'll be back in within 10 minutes.