When I try to start CNTLM, it fails. If I check in my Windows Event Log I see the message:

starting service 'cntlm' failed: fork 11, Resource temporarily unavailable

It worked before I updated to the latest Windows 10 (from 1511 to 1607). How can I solve this issue? (I already reinstalled CNTLM).


3 Answers 3


This worked for me on Win 10 1607:

Open regedit.exe and go to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\cntlm\Parameters.

Then change the AppArgs key to -f -c "C:\Program Files (x86)\Cntlm\cntlm.ini"

  • In my case, -f -c "C:\Program Files (x86)\Cntlm\cntlm.ini" did not work but -f -c "/cygdrive/c/Program Files (x86)/Cntlm/cntlm.ini" did. Feb 7, 2020 at 13:26
  • you save my day!
    – Tano
    May 26, 2020 at 7:48

Latest cntlm-0.92.3-setup.exe installed the service but it couldn't start. I tried every combination of params under different users by failed to make the bundled cygrunsrv.exe to successfully start cntlm.exe as windows service under W2k3 x64.

While it run fine without service:

cntlm.exe -T "C:\Program Files (x86)\Cntlm\debug.txt" -v -f -s -c "C:\Program Files (x86)\Cntlm\cntlm.ini"

Had to work this around by switching to srvany. It's just needed to copy srvany.exe from Windows Server 2003 Resourse Kit and run the following commands to repair the existing cntlm service:

reg ADD HKLM\SYSTEM\CurrentControlSet\Services\cntlm /v ImagePath /t REG_EXPAND_SZ /d "C:\Program Files (x86)\Cntlm\srvany.exe" /f
reg ADD HKLM\SYSTEM\CurrentControlSet\Services\cntlm\Parameters /v Application /d "C:\Program Files (x86)\Cntlm\cntlm.exe" /f
reg ADD HKLM\SYSTEM\CurrentControlSet\Services\cntlm\Parameters /v AppDirectory /d "C:\Program Files (x86)\Cntlm" /f
reg ADD HKLM\SYSTEM\CurrentControlSet\Services\cntlm\Parameters /v AppParameters /d "-T \"C:\Program Files (x86)\Cntlm\debug.txt\" -v -f -c \"C:\Program Files (x86)\Cntlm\cntlm.ini\"" /f

As of today, the best solution is to change the NTLM proxy application you use. CNTLM is outdated and not maintained anymore, and shows even more issues in recent Windows 10 builds.

You would better switch to Px, which is also open source and

is a HTTP(s) proxy server that allows applications to authenticate through an NTLM or Kerberos proxy server

It is more secure than CNTLM, because Px doesn't even ask you to save password or password hashes to the config (which was instead required in CNTLM) and transparently uses the credentials of the current Window session, and you can also configure it to use a PAC (Proxy Auto-Config) file instead of specifying a single proxy server (which was another severe limitation in CNTLM).

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