Why is loaded dll missing in Visual Studio's modules list?

Question

I am currently bug hunting and need to debug into a specific dll in the release configuration in Visual Studio 2005. At some point I closed the solution, did some other stuff and reloaded it. From that point on my breakpoint doesn't get hit and I get the infamous "No symbols have been loaded..." message. So I opened the modules window and the dll that I want to debug doesn't appear in the list anymore, therefore I cannot load symbols manually. The application behaves normal so I am absolutely sure that the dll MUST have been loaded to execute certain functions. Sure enough, if I rename the dll and start up the application it doesn't work anymore, so it also must be the right dll.

I tried setting the dll project as startup project and the command to execute to the application's exe and starting the application from outside visual studio and then attaching to the process, all to no avail.

Question is, why is the dll not appearing in the list of loaded modules although it must have been loaded? I cannot think of any other changes that I've done, that could cause this, am I missing something? (Maybe something really obvious?)

Any help appreciated!

Answer 1

1. Use process explorer to check if the dll is loaded or not.

2. When you attach the process make sure that you are enabling both 'Native' and 'Managed' code type (in the code type selection option).

See also this question: Visual Studio is not loading modules when attaching to process

Answer 2

I encountered a similar issue after transferring a project from one computer to another. I will simply explain what I discovered and how I fixed it, and you can determine if it fits your problem and solution.

1. The work computer I wrote an application on contained a .dll file which my program was referencing. After moving the application to my home computer, the application could no longer locate the .dll file it was previously referencing because the file was no longer there.

2. The application compiled and ran even without the referenced resource (.dll file) because the previously compiled assembly (debug folder) contained its own copy of the .dll file and other resources. Put simply, it is the old assembly build that is running and not the current application you're working on. This is also why this error tends to suspend the designer window and throw an error after the app is done running.

I would take a look at the following:

a) Under Solution Explorer, go into the References folder and right click the missing reference node and select properties. In the properties box, observe the Path of the resource being referenced. Is the resource still located at this path?

b) Check the debug folder for a copy of the resource you're looking for. If the resource is there, make a copy and save it to your desktop. If it's not there, get the file from the original source.

c) Under Solution Explorer, right click 'Properties' and 'open'. From the menu that appears select 'Resources' from the left and at the top of the new window that appears you you should see 'Add Resource' with a small drop down arrow. Click the arrow and select 'Add existing file' and then browse to the file. If you don't see it you may have to change the file being browsed from the small drop down above the 'open' and 'Cancel' buttons. After the file is located it should create a new folder in the solution explorer called 'resources.' Now the file is a permanent part of your application and not merely a reference to it.