Hello @Thomas Pirro ,
What’s your detailed Outlook version? 32 bits or 64 bits?
Can you choose “Save this invitation as a file” and proceed with the next step?
For your reference:
https://www.technipages.com/windows-send-remote-assistance-invitation
https://social.technet.microsoft.com/Forums/en-US/c576cae0-d1dc-4026-9676-5124b2ca6b96/outlook-not-recognised-as-default-client?forum=outlook
https://www.slipstick.com/outlook/outlook-not-recognized-default-email-client/
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Best regards,
Leila
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