How to Debug Silverlight Applications on 64 Bit Windows when IE 11 is installed

Introduction

Did you ever come across this error message when trying to debug a Silverlight application with Internet Explorer 11 on a 64 bit OS like Windows 7 x64?

Maybe this tip can help you.

Background

The reason for this lies in a registry setting called TabProcGrowth.

TabProcGrowth = 0:
Tabs run in the same process as the manager process.
On 64 bit Windows, all tabs are running as 64 bit.
This is what Visual Studio is complaining about.

TabProcGrowth = 1:
Tabs run in a different process.

Using the Code

In order to allow debugging, you must set the following registry key to 1:

HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Main\TabProcGrowth

If this value does not exist, you must create it yourself. Make sure it is a DWORD (32-bit value).

Don't forget to restart your Internet Explorer.