C＃Visual Studio启动调试器时挂了很长时间

Question

My Winforms app has a reference to a local DLL file called MyUtilities.dll. Whenever I start debugging my app after making ANY code change and it reaches the point where it uses a method inside MyUtilities.dll to make a network call to a remote SOAP API, VS hangs for about 90 seconds and when I try to click anywhere inside VS, it brings up the popup that says it's "Loading symbols for MyUtilities.dll".

Here's where it gets interesting:

1. The PDB file is not encrypted with EFS.
2. Just My Code debugging is enabled.
3. I've even added MyUtilities.dll to the exclusion list.
4. The CPU usage doesn't really spike when it's hanging.
5. I've tried to use Process Monitor (procmon) to watch the activity, and I don't see anything unusual, but I might be looking at the wrong thing...
6. I've loaded Fiddler at the same time to see if it's a long remote API call but the SSL handshake and network call don't even begin until the ~90 seconds is finished, and the actual API call comes back in under 1 second.
7. I've tried copying the DLL file to a different folder on an SSD and referencing it from there, but it doesn't make a difference.
8. If I start/restart the debugger again without any code changes, it does not freeze.

Now, AFTER it resumes running, I can see in the output that it didn't load the symbols):

'MyApp.exe' (blah blah): Loaded 'C:\...\bin\Debug\MyUtilities.dll'. Loading disabled by Include/Exclude setting.

Any ideas on what could be causing the freeze? I'm running VS 2017 Community.

Answer 1

Figured it out. After some more analysis in Process Monitor, I noticed entries for "MAILSLOT\\NET\\NETLOGON" like:

11:21:04    CreateFile    \\MYPC*\MAILSLOT\NET\NETLOGIN    SUCCESS
11:21:04    WriteFile     \\MYPC*\MAILSLOT\NET\NETLOGIN    BAD NETWORK PATH
11:21:17    CloseFile     \\MYPC*\MAILSLOT\NET\NETLOGIN    SUCCESS

Based on that, I found this StackOverflow question: Visual studio 2012 slow unit testing

...which led me to this article: https://social.technet.microsoft.com/Forums/windowsserver/en-US/20eb50e9-3e68-4d29-bcdd-a4fc166b9c00/adlds-very-slow-roundtrip-to-servermailslotnetnetlogon?forum=winserverDS

End Result: Go into each network adapter, go to its properties, go into the Internet Protocol Version 4 (TCP/IPv4) properties, go to Advanced -> WINS and disable NetBIOS over TCP/IP.

After doing that, everything works perfectly (didn't even need to reboot).