outlook 2010 - why does it want to downlad files?

When I open Outlook 2010 (packaged with Office 2010), I immediately get a File Download screen asking if I want to Open Save or Cancel the download of a file called....."
{7CCO9FE-B62D-4554 (etc, etc) }.html;
next line....a Firefox Document of 6.40KB,
next line:.....from C:\Users\mycomputer\AppData\ (etc etc)

If I cancel this screen it closes and there may or may not be another similar one underneath with a different file name; the app then seems to work OK. If I click 'Open' then my browser (Firefox) opens with the file name in the URL slot with the message there is nothing to find (!)

If I open any message or any other part of the app I get the same screen but a different file name.

I have asked Microsoft and they answered that if when I open it in Outlook in Safe Mode then I need to make changes to my Add Ins but they haven't said what, which or why.

Any ideas how I can get a £120 app to work properly?

Link to another (non-Microsoft) forum removed.

What happens if you allow it to download? Does it go away or return the next time you open Outlook?

Microsoft may have subscribed you to a newsletter (or even some RSS feed). I know they used to send a Microsoft newsletter to older versions of Outlook. If so you would need to check your settings to turn off or unsubscribe.

BTW. Outlook was never a replacement for Outlook Express. Outlook is a much more structured email system including an organizational calendar system and has been bundled with Office for a long time (primarily as an attempt to put Lotus Notes out of business). The old Outlook Express is a stripped down version and has been replaced with windows Live Mail which is part of windows Live Essentials.

Thank you for your interest. If I allow the download I get the little screen of an envelope flying between two points but it never downloads anything - it goes on forever (tested over several hours). I simply cannot fathom out why or what is going on and how to cure it.

Reference to your other point:
We bought this Outlook as we have used OE for years, decades even, and like its simplicity and ease; you see all the messages coming in, they're displayed together regardless of the 7 different accounts we use and the outbox allows us to queue all our messages until we choose to send them. Am an expert now with Pegasus, Thunderbird, Eudora and a few others, tried them all and prefer OE so we bought Outlook......and all because Windows 7 doesn't support OE.

It has been doing this since the day you installed it?

When you do cancel, does your regular mail send and receive properly or is that blocked too?

Information not getting through could be a firewall issue or the Anti-Virus having a problem scanning it as email. What AV software do you use? Try turning it off once and then open Outlook and allow the download.

Also, I notice on your post to Microsoft you say the folder doesn't even exist. Getting you to at least see the folder I can definitely help with. That would be a hidden file folder and so the only way to see it is to change your settings (in windows explorer, tools...folder options...view, select Show hidden files, folders, or drives) or to use an environment variable to backdoor into it; in Windows Explorer type:
%localappdata%\Microsoft\Windows\Temporary Internet Files
(jut FYI the %20 is html for a space which is why it is "Temporary Internet Files")

Have you tried uninstalling and reinstalling Outlook? (Be sure to back up your mail first if you try this)