So out of the blue today, I click a link embedded in an e-mail, and Outlook gives me this error:
General failure. The URL was: "http://www.someURL.com" The system cannot find the file specified.
Oh, Outlook. If I had a nickel for every weird, random error you've produced over the years, I'd be sitting on a wheelbarrow full of nickels. (FWIW, I made up the "someURL" part.)
This is a known bug, and has been for years. It occurs when Firefox is your default browser and some glitch (or program) changes that default. Thankfully, there's a fairly easy fix, though it does involve monkeying around in the Registry.
(Note: These instructions apply to Windows Vista and 7 only.)
1. Click Start, type regedit, and then press Enter.
2. Navigate to the following entry: HKEY_CLASSES_ROOT\FirefoxURL\shell\open\ddeexec
3. In the center pane, double-click the Default entry, then remove whatever value is there (it'll probably be a weird string of numbers and commas).
4. Click OK, then exit Regedit.
5. If Outlook and/or Firefox are open, close them, then restart them.
That should do the trick! If it doesn't work for you, let me know (firstname.lastname@example.org) and I'll steer you to some other options.
Update: A Microsoft repesentative suggested this fix for the "general failure" error.