How to check ASP.NET Version loaded on a system?

Solution 1:

You can use

<%
Response.Write("Version: " + System.Environment.Version.ToString());
%>

That will get the currently running version. You can check the registry for all installed versions at:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP

Solution 2:

You can see which version gets executed when you load the page with Google Chrome + developer tools (preinstalled) or Firefox + Firebug (add-on).

I use Google Chrome:

1. Open Chrome and use Ctrl+Shift+I to open the developer tools.
2. Go to the "Network" Tab
3. Click on the small button at the bottom "Preserve log upon Navigation"
4. Load any of your pages
5. Click on the response header

It looks like this: