Skype Won’t Login

This post was migrated from my older blog.

We had an issue a while ago where Skype would not sign several users in. There was nothing obvious from Skype itself, no errors, no timeouts. It just sat there spinning. I opened up WireShark and found no packets were even being attempted from Skype to our server. In procmon, I similarly found nothing happening after the logon is attempted, no errors, no network traffic, no access denied, etc. A coworker finally managed to get some headway by noticing that all affected users had no network connections shown in the Network and Sharing center. This was odd as they did have internet access; could check e-mail, browse the internet, access domain resources, etc. It turns out, the cause was permissions on a specific set of registry keys dealing with network information. Specifically the netprofm account did not have access to the following registry keys

HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList
HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\NetworkList\Profiles

Once the permissions were corrected, Network and Sharing center showed our domain connection and Skype started functioning, didn’t even require a reboot.