Turning Off “New Outlook” in Outlook 16.58

SpamSieve
1

There’s a bug in Outlook for Mac 16.58 where the switch to turn off New Outlook is missing. This is especially a problem because at launch it encourages users to opt into the New Look without telling which features (including some required by SpamSieve) will be lost by doing so. The release notes claim that the switch has been restored, but I found that even in the 16.59 beta the switch is still gone. You can, however, turn off New Outlook by entering this command in Terminal:

defaults write com.microsoft.Outlook IsRunningNewOutlook NO

and then restarting the app.

2

This Terminal command also works in Outlook 16.7, if you have a Microsoft 365 subscription. The new free version only works in “New Outlook” mode.

3

I have tried the command in terminal and it doesn’t work for me. Outlook updated tp “New” after I restarted even though I didn’t ask it to. Now I am stuck with no SpamSieve. I would go back to Apple mail but my ISP doesn’t like it.

4

Which version of Outlook are you using? The current one in the Mac App Store is 16.73.1, and with that version I find that the Terminal command works but isn’t necessary because there is a toggle in the Outlook menu.