I haven’t ever worried about this, but I had the need recently to check. I was looking a SQL Sentry’s Plan Explorer and the instructions mentioned that you need the .NET Framework v4.0 installed.

So I decided to check my machine. First I hit Control Panel

However that doesn’t say .NET 4.0 install. Instead it has a “client profile” listed. What does that mean?

I wasn’t confident of this, so I Google’d for the question. I found this blog on How to Check. It lists a Javascript call that you can paste into IE or Firefox.

javascript:alert(navigator.userAgent)

I get this from Firefox:

and this from IE:

Again, .NET4 is listed, but not with a CLR component. So I’m not sure what I have.

Then I went over to Stack Overflow to check. I would this answer, and it lists registry keys. I checked mine and I see this:

So do I have .NET 4.0 or not? At this point I’m still not since it’s hard to determine if I really have the CLR needed. So I decide to just install Plan Explorer and look for error messages.

Pow! Apparently the client profile isn’t enough. So I downloaded the .NET 4 Framework from the link at SQLSentry and then saw this:

.NET Framework extended, which matches the result from IE:

Now I can go play with SQL Sentry’s Plan Explorer. It certainly look cool!