Running unit tests on VS2012 is lately very slow, when I run them it

Question

Asked: June 15, 20262026-06-15T16:33:08+00:00 2026-06-15T16:33:08+00:00

Running unit tests on VS2012 is lately very slow, when I run them it takes about 12 seconds before they start actually testing.

When I debug it is the same story before I hit the first breakpoint.

I hooked up process monitor and then I found this:

CreateFile \\WORKSTATION*\MAILSLOT\NET\NETLOGON SUCCESS

WriteFile \\WORKSTATION*\MAILSLOT\NET\NETLOGON BAD NETWORK PATH

After that it stays 9 seconds quiet.

CloseFile \\WORKSTATION*\MAILSLOT\NET\NETLOGON SUCCESS

What on earth is going on here? I cannot find any relation between MAILSLOT and Visual Studio at all, but it is going on for about 2 weeks now.

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Editorial Team · Answer 1 · 2026-06-15T16:33:10+00:00

Editorial Team

I had the same issue, using VS2012 Update 1. Based on the suggestion in http://social.technet.microsoft.com/Forums/en-US/winserverDS/thread/20eb50e9-3e68-4d29-bcdd-a4fc166b9c00 I disabled NetBios over TCP on my NIC. The tests now start up immediately, and procmon shows the time waiting on \MACHINE*\MAILSLOT\NET\NETLOGON dropped from 5 seconds to about 40 microseconds.

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