Systems that use Windows Mail as their default mail client have periodically been forced into using the new Outlook Preview for last year or so, because Microsoft effectively launch-hijacks Windows Mail to automatically switch to Outlook Preview.
Previously Microsoft included a toggle upper-right that reverted Outlook Preview back to Windows Mail. However, this button/option looks to have been removed with the latest Windows Update.
The RegEdit instructions highlighted to fix this in the Microsoft Support article “Toggling out of the new Outlook for Windows preview” only refer to “classic Outlook” and not Windows Mail; there is no UseNewOutlook entry in Mail based systems (unless Office has been installed), so no “Value Data field” available to be set to “0“.
Revert to Windows Mail
To revert back to Windows Mail from within Outlook Preview; after Outlook Preview has opened;
- click on Settings (cog icon upper-right).
- then on General
- finally on About Outlook
At the bottom of the page is
- Return to Windows Mail and Calendar.
Click the Open Mail now button.
It’s important to note this is not a permanent fix for Outlook Preview hijacking Windows Mail (per the message displayed above the button).
Uninstall Outlook Preview
As an alternative it may be possible to delay the forced switch to Outlook Preview by uninstalling the application;
- From Windows Desktop click Start then Settings.
- In Settings click Apps, then Apps & features.
In the list in the main area Outlook (new) should be shown. Click Uninstall as normal to remove.
Note that, as with all the options to revert back to Windows Mail, uninstalling Outlook (new) is temporary as the application may been (re)installed during the next scheduled Windows Update.
(Re)Set Default Apps
Another temporary alternative to the above is the (re)set the default application used to manage email;
- From Windows Desktop click Start then Settings.
- Then in Settings click Apps, then Default apps;
Email should be shown under the Choose default applications list in the main area. Here;
- Click the Outlook (new) icon and select (or search for) Mail.
This resets the default application to open Windows Mail.
Note again that this is not a permanent solution as Windows may automatically (re)set Outlook (new) the next time Windows Mail is launched.
