Today finally I decided to uninstall SP1 of Visual Studio 2010. A sad decision, because I like to have the latest service packs and hotfixes, but my definition of service pack is something that fixes bugs, not introducing new ones, and SP1 introduces these two issues (a bug and a “by design” change actually) that I can’t stand anymore, and that are not going to be fixed:

VS 2010 SP1 breaks add-in debugging targetting .NET Framework 2.0 rather than .NET Framework
https://www.visualstudioextensibility.com/2011/03/15/vs-2010-sp1-breaks-add-in-debugging-targetting-net-framework-2-0-rather-than-net-framework

VS 2010 SP1 changing “ByVal” VB.NET code editor experience
https://www.visualstudioextensibility.com/2011/03/15/vs-2010-sp1-changing-quot-byval-quot-vb-net-code-editor-experience

I guessed that uninstalling SP1 from my laptop and my desktop computers was going to be long, and certainly it was so. Furthermore, it was annoying because the uninstaller asks for the original installation sources, even the installation source of Visual Studio 2010 Express Edition for one specific component (which I think never was installed on the computer that prompted for them, the other didn’t). Not only uninstalling SP1 is a long procedure (not unattended due to the source installation prompts) , but also you must reinstall or repair Visual Studio after uninstalling SP1. All of these are known issues described in the readme of Visual Studio 2010 SP1:

Visual Studio SP1 Readme:
http://go.microsoft.com/fwlink/?LinkId=210711

After a couple of (wasted) hours, I think that both Visual Studio 2010 installations are working again, without SP1.