I am using a Mac with OS X 10.6. The Firefox version is 11.0. we cannot authenticate to https:// sites that require NTLMv2. We were able to use Firefox on the Mac to authenticate to https:// sites until our organization dropped NTLMv1 and required the use of NTLMv2. The problem on the PC was corrected by using the NTLM plugin but we have never managed to correct the problem on the Mac. The operating system does not appear to be the problem since Safari can authenticate to these sites. I have added the https:// url to the network.negotiate-auth.delegation-uris, network.negotiate-auth.trusted-uris and the network.automatic-ntlm-auth.trusted-uris parameters (which is necessary to correct the problem on the PC). After reading the thread about ntlmv2 authentication in Lion I also set network.automatic-ntlm-auth.allow-proxies and network.negotiate-auth.allow-proxies to false but I still can't authenticate. I also tried creating an nsmb.conf file in /etc with minauth=ntlmv2