Getting "Unable to step. The operation could not be completed. A retry should be performed" while debugging in Visual Studio

Problem Description

Getting below error messages while debugging an ASP.NET website in Visual Studio 2005 SP1

when stepping through, getting

    "Unable to step. The operation could not be completed. A retry should be performed"

After clicking OK on the dialog, getting

    "The debugger cannot continue running the process. The operation could not be completed. A retry should be performed."


A known issue with the Visual Studio debugger causing this problem. There is a race condition that happens when all of the following are true:

1. Script debugging is enabled in IE
2. User is debugging IE and another process
3. The other process stops (hits breakpoint, step operation completes, stops at an exception, etc) at a moment when IE is not running script code
4. IE starts running script code at roughly the same moment that the user hits F10/F5 in Visual Studio. The most likely reason for this to happen is that the code from 'setTimeout' is run - there could be other reasons as well.


1. If you hit this problem, you can try detaching and reattaching the debugger.

2. This problem happens when debugging ASP.NET and when script debugging is enabled in IE. If you disable script debugging in IE, or toggle it on and off when switching between debugger server-side and client-side problems, you would be able to work around the issue.

3. If your web application is using setTimeout, you may be able to avoid or at least reduce the problem by doing something to ensure that script runs less often. This could mean increasing the timeout value, or this could mean adding conditions around when setTimeout is used.

Above are the recommendations made by Gregg Miskelly of Visual Studio debugger development team. I’ve worked on this issue from developer support reported by one of our extremely helpful customer who gave us a perfect environment to troubleshoot and identify this issue. For this case I’ve worked on, disabling the script debugging in IE made the trick.

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