I have just discovered exactly what works for me with the same problem but in Outlook 2013. I have a different key (lets say it's called webpage
) under HKCU
that has my default browser shell associations. The .html
key points to it: (default) = webpage
.
Firefox is the default browser under keys HKCU\webpage\shell\firefox
but Outlook gives me the error Your organization's policies are preventing us from completing this action for you. For more info, please contact your help desk.
even though Firefox works as my default browser in every other app (that I have used it in, probably haven't tried Excel).
When I add keys HKCU\webpage\shell\open\command
without any (default)
values or any other values and restart Outlook, my links work as expected. Seems as though Outlook is, for some reason, checking that these keys exist, even though it doesn't actually use them, as my link opens in Firefox still.
UPDATE: Windows 10.1709 appears to now not only require the open shell command but also USE it, even though it's not listed as the default, so you now need to have the command
's (default)
value populated. I see this same behaviour with Thunderbird and just pasting a URL into the start run dialog as well.
HKEY_CLASSES_ROOT\.html
and others' Default Value (the@="htmlfile"
bit below) as"FirefoxHTML"
. Thanks all. – Chrisman