Issue
You have installed Microsoft Outlook configured as the default mail client. The following message is displayed when started Outlook:
Either there is no default mail client or the current mail client cannot fulfill the messaging request. Please run Microsoft Outlook and set it as the default mail client.
Solution
The cause of this problem is that Microsoft's API of localized versions of Microsoft Outlook is not registered correctly in HLKM\Software\Microsoft\Windows\CurrentVersion\Installer...
To solve this problem do the following:
- Do not use Office from Microsoft Store. Use Microsoft Office 365 or Microsoft Office 2016 instead of it.
- Install the latest applicable updates for Microsoft Outlook.
If you set Outlook as the default email client and the issue still persists, you can disable Integrate into Microsoft Outlook in Advanced setup (F5) > Web and email > Email client protection > Email clients.