“Setup cannot continue because a more recent version of Internet Explorer has been detected on this computer.”

Recently while performing a Windows Update my Vista box locked up.  The update ( for Internet Explorer 8 ) hadn’t quite completed and when I restarted, IE 8 was installed and running fine but my Windows Update didn’t think so.

My first thought was to remove IE 8, surely a re-install would solve the problem.  I followed the advice on Microsoft’s support site ( http://support.microsoft.com/kb/957700 ) for removing IE and neither the standard or alternative instructions worked for me.

After days without a resolution I finally figured out how to re-install IE 8 ( of course, you will only need to perform this hack if the Microsoft’s recommendations don’t work for you ).  Here is how to do it:

1. Download IE 8.
2. Run the installer and wait for the “Setup cannot continue because a more recent version of Internet Explorer has been detected on this computer.” prompt to appear.  DO NOT CLOSE THE PROMPT – if you close the prompt this will not work as the temporary directory mentioned in the next step will be removed.
3. The installer is extracted to one of your drives ( in my case it was not my C drive, so make sure you look at all of your available drives ) in a directory named with a random key ( in my case the key was 5c5c0d193eca399daddb3768b3 ).  Find the directory, open it, and run ie8.msu.  This will allow the installer to run and you will be up and running.

Any developer that has worked on web interfaces knows the pains involved in dealing with different browsers and browser versions.  Microsoft  has notoriously made this difficult by not permitting more than one version of IE to run on a machine.  The solution – install a VM for each version of IE you want to run.  Does that sound crazy to you?  It does to me.

I recommend using one of the following tools to accomplish the same thing:

1. http://spoon.net/browsers/ – My first recommendation.
2. http://www.my-debugbar.com/wiki/IETester/HomePage – Seems to work pretty well.

I have to test things on different browser versions regularly due to my work on DWR and both of these tools have been a tremendous help.