visual-studiovisual-studio-2008edit-and-continue

Edit and Continue: "Changes are not allowed when..."

Even if I create a clean WinForms project, Edit and Continue doesn't work and gives me the error:

Changes are not allowed when the debugger has been attached to an already running process or the code being debugged was optimized at build or run time.

  1. Edit and Continue option is checked in Tools → Options → Debugging.
  2. Optimization is not enabled.
  3. Seems like there is no any managed profiler set up.
  4. I am running in Debug mode
  5. I am running on x64 CPU and Windows XP 32-bit, but setting platform target to x86 rather than AnyCpu doesn't help.
  6. Repairing Visual Studio installation doesn't help.

I also found this article on MSDN website:

Unsupported Scenarios

Edit and Continue is not available in the following debugging scenarios:

  • Debugging on Windows 98.

  • Mixed-mode (native/managed) debugging.

  • SQL debugging.

  • Debugging a Dr. Watson dump.

  • Editing code after an unhandled exception, when the "Unwind the call stack on unhandled exceptions" option is not selected.

  • Debugging an embedded runtime application.

  • Debugging an application with Attach to rather than running the application with Start from the Debug menu.

  • Debugging optimized code.

  • Debugging managed code when the target is a 64-bit application. If you want to use Edit and Continue, you must set the target to x86. (Project Properties, Compile tab, Advanced Compiler setting.).

  • Debugging an old version of your code after a new version failed to build due to build errors.

But I can answer "No" to every item in this list.

It worked before, but several days ago it stopped working, and I don't know what could be the reason.

Solution

  • I finally got to solve the problem: UNINSTALL Gallio

    Gallio seems to have quite some many rough edges and it's better to not use MbUnit 3.0 but use the MbUnit 2.0 framework but use the gallio runner, that you are running without installing from the installer (which also installed a visual studio plugin).

    Incidentally, I had the issue even after "disabling" he Gallio plugin. Only the uninstall solved the problem.

    PS. Edited by nightcoder:
    In my case disabling TypeMock Isolator (mocking framework) finally helped! Edit & Continue now works!!!

    Here is the answer from TypeMock support:

    After looking further into the edit and continue issue, and conversing about it with Microsoft, we reached the conclusion it cannot be resolved for Isolator. Isolator implements a CLR profiler, and according to our research, once a CLR profiler is enabled and attached, edit and continue is automatically disabled. I'm sorry to say this is no longer considered a bug, but rather a limitation of Isolator.