After returning from TechEd Berlin this Friday, I downloaded and install the recent release of the ASP.NET MVC 3 RC build. Everything seemed fine, until I tried to debug something inside Visual Studio. I couldn’t do any kind of useful debugging.
I found out on Scott Guthrie’s blog that it’s a known issue caused by installing both ASP.NET MVC 3 RC and C#/VB Async CTP. At this moment it isn’t possible to have both the Async CTP and the ASP.NET MVC 3 RC installed on the same machine at the same time. You instead need to choose one or the other right now – installing both will cause problems.
To fix this, go to Add/Remove Programs and uninstall both the ASP.NET MVC 3 RC build (including the VS Tools components for it) and the Async CTP. Once you’ve uninstalled both your machine will be back to a clean state and working fine. You can then choose to install either the Async CTP or ASP.NET MVC 3 RC and it will work fine.
Async CTP Uninstall Instructions
The Microsoft Visual Studio Async CTP is installed as two updates:
1) .NET Framework 4.0 update called “.NET Framework Async CTP”
2) Microsoft Visual Studio 2010 update called “Microsoft Visual Studio Async CTP”
To uninstall go to Control Panel > Programs and Features > View installed updates. You will need to uninstall both updates.
ASP.NET MVC 3 RC Uninstall Instructions
To completely uninstall MVC 3 RC, you actually need to uninstall all of the following:
- Microsoft ASP.NET MVC 3
- Microsoft ASP.NET MVC 3 - Visual Studio 2010 Tools (only installed when you have Visual Studio 2010)
- Microsoft ASP.NET MVC 3 - VWD Express 2010 Tools (only installed if you have Visual Web Developer 2010 Express)
- Microsoft ASP.NET Web Pages
- Microsoft ASP.NET Web Pages - Visual Studio 2010 Tools (only installed when you have Visual Studio 2010)
- Microsoft ASP.NET Web Pages - VWD Express 2010 Tools (only installed if you have Visual Web Developer 2010 Express)
- NuGet
- Update for Microsoft Visual Studio 2010 - (KB2385361) (only installed when you have Visual Studio 2010)
- Update for Microsoft Visual Web Developer 2010 Express - (KB2385361) (only installed if you have Visual Web Developer 2010 Express)