Outlook opens a browser page

[Amelia43]

I have been happily using OL 2010 (a component of Office 2010 Pro) since the beta days. Recently when I open OL and click on an email, a browser page (Firefox is my default browser) opens, and the URL gives a file path in the Application Data/Local/Temp folder (see attached). This folder differs from the Outlook Secure Temp folder (according to an exploration of the registry). The behaviour is annoying as there is a delay while file download occurs and the the web page opens. The problem does not apply only to emails with attachments. Otherwise OL is behaving properly.
I had tried and uninstalled a couple of add-ons (Blueprint for Outlook and Vcard Wizard for Outlook) as they both caused problems- the former opened a web page with the wlecome screen and the latter would not work- also opened a a web page with gobbldegook.
I have throughly uninstalled both add-ins (Revo Pro Uninstaller) and cleaned up the registry and temp files with CCleaner. I uninstalled and reinstalled Office, cleaned up again, but the problem persists ( I am reusing my original pst files).
I would appreciate any suggestions on what might be causing this behaviour and how I might overcome it.
Sincere thanks
Dianne

OL html file.docx

[HansV]

The problem is mentioned elsewhere, but without a satisfactory solution. One suggestion was that the problem goes away if you set Internet Explorer as default browser...

[Amelia43]

Thank you for your as always prompt and concise reply. I did think of that solution, but delayed implementing it. Will give it a try and report back.
All the best
Dianne

[Amelia43]

Yes, Hans, the solution was to switch to IE as the default browser. A test switch back to FF reproduced the problem with a vengeance! Having been a Firefox user and enthhusiast for some time, it has been a difficult sacrifice to make, but saves the irritation and delay of the peculiar Outlook behaviour. Will have to do my homework and learn how to configure IE to meet my needs.
All the best, and thank you
Dianne

[Amelia43]

I'm not sure whether this is a permanent fix, but I cleaned the Firefox cache and reset FF as the default browser-so far the problem has not recurred- only time will tell!
Dianne

[HansV]

Let's hope it'll stay fixed!

[Amelia43]

After the many hours I've spentfruitlessly researching the problem, and missing my customised and friendly Firefox, I am amazed that the "fix" could be so simple. It may be too good to be true! But perhaps desperation leads to inspiration....
Dianne