Visual Studio loading symbols

Question

I'm working on a ColdFusion project for a while now, and Visual Studio started to behave strange for me at least.

I observed that when I started debugging, it built the project, it started the deploy, and the deploy finished and it was starting to load symbols for my project.

But it was very slow, and I don't know why it started to do this step. What may I have done?

Is this symbol loading step necessary? How can I disable it?

In the Tools -> Options -> Debugging -> Symbols dialog there is no Symbol file (.pdb) location added. And I pointed in my project's debug directory at the field below, and I checked the "Search the above directory only when symbols are ...." checkbox. How should I set up this dialog to turn off symbol loading?

I looked in the Modules window which symbols are loaded, but it says nothing to me. What is the problem?

Answer 1

Configure in Tools, Options, Debugging, Symbols.

You can watch the output window (view, output) to see what it's doing usually. If it's really slow that probably means it's hitting a symbol server, probably Microsoft's, to download missing symbols. This takes three HTTP hits for each file it can't find on every startup - you can sometimes see this in the status bar at the bottom or in e.g. Fiddler. You can see which modules have loaded symbols in Debug, Windows, Modules whilst you're debugging.

Symbols mean you get useful stack trace information into third party and system assemblies. You definitely need them for your own code, but I think those get loaded regardless. Your best bet is to turn off any non-local symbol sources in that menu and, if you're loading lots of symbols for system assemblies that you don't need to debug into you can temporarily disable loading those to speed up debug start - but they're often useful to have loaded.

Answer 2

I faced a similar problem. In my case I had set _NT_SYMBOL_PATH to download from Microsoft Servers for use in WinDbg and it looks like when set, Visual Studio will use that with no way to ignore it. Removing that environment variable resolved my issue.

Answer 3

For me, it seems related to breakpoints, as indicated in the accepted answer. However, I found two workarounds that did not involve deleting all the breakpoints:

• Restarting Visual Studio seemed to fix it temporarily.
• Clicking the "X" button to close Visual Studio while debugging causes the "Do you want to stop debugging?" message box to pop up; while this message box is up, the symbols load at ordinary speeds. Once all the symbols are loaded, you can click "No" to cancel the close.

Answer 4

Just encountered this issue. Deleting breakpoints didn't work, or at least not just on its own. After this failed I Went Tools > Options > Debugging > Symbols and "Empty Symbol Cache"

and then cleaned the solution and rebuilt.

Now seems to be working correctly. So if you try all the other things listed, and it still makes no differnce, these additional bits of info may help...

Answer 5

Visual Studio 2017 Debug symbol "speed-up" options, assuming you haven't gone crazy on option-customization already:

1. At Tools -> Options -> Debugging -> Symbols
   a. Enable the "Microsoft Symbol Server" option
   b. Click "Empty Symbol Cache"
   c. Set your symbol cache to an easy to find spot, like C:\dbg_symbols or %USERPROFILE%\dbg_symbols
2. After re-running Debug, let it load all the symbols once, from start-to-end, or as much as reasonably possible.

1A and 2 are the most important steps. 1B and 1C are just helpful changes to help you keep track of your symbols.

After your app has loaded all the symbols at least once and debugging didn't prematurely terminate, those symbols should be quickly loaded the next time debug runs.

I've noticed that if I cancel a debug-run, I have to reload those symbols, as I'm guessing they're "cleaned" up if newly introduced and suddenly cancelled. I understand the core rationale for that kind of flow, but in this case it seems poorly thought out.

Answer 6

My 2 cents,

I was having a similar problem while trying to get a (Visual Studio 2013) Diagnostics Report in x64 Release Mode (CPU Sampling) and while the symbols for the needed dll files were loaded, the symbols for my executable would fail to load.

I didn't change anything in the Symbols menu, I instead made some changes within the Property Pages of my executable's thread in the Solution Explorer, namely

Configuration Properties / General / Enable Managed Incremental Build to YES

Configuration Properties / Debugging / Merge Environment to NO

Configuration Properties / C/C++ / Enable Browse Information to YES (/FR)

Configuration Properties / Linker / Enable Incremental Linking to YES (/INCREMENTAL)

EDIT : This last one does the trick

....

Configuration Properties / Linker / Debugging / Generate Debug Info to Yes (/DEBUG)

....

After that it worked and it loaded the symbols fine. I'm sure one or more of the above did the trick for me (although I'm not sure exactly which) and just want to let others know and try this..

peace