Unable to start debugging: the version of clr.dll...

So, this morning I arrive at work, I boot my pc, open Visual Studio and get to it. I do some coding and when I want to run my project (for the first time today) to test the changes I get this thrown at me:

It was fine the day before and there were no problems loading the project or whatever, so you could call this strange to say the least :( My first Google search said re-install, but luckily it didn't go that far. So for all those that get confronted with this problem, I made an overview of what causes this problem and how to fix it!

Possible causes

• faulty configuration
• misfortune
• conflicting updates

Possible solutions

• Just reboot Visual Studio... if you are as lucky as me, this could save your day!
• Check the targeted platform: in your project properties > Compile tab > Advanced options.
  If this has defaulted to the .NET 4.0 Client Profile, this could cause the problem.
• Check if Windows is currently installing updates or if recent updates have failed. If so, finish or fix the installation of these updates first.
• Re-install Visual Studio, yes that sucks, I know!
• Update Visual Studio to Service Pack 1.

Good luck and I hope this helps resolve the problem for you!


Could be useful, right?