I was working with a client who says everything from Outlook opens in Microsoft Edge even though Chrome is his default browser.
I used the two tools – setdefaultbrowser.exe and setuserFTA.exe to reset default browser settings and file associations all with Google Chrome instead of Edge:
SetDefaultBrowser.exe HKLM “Google Chrome”
SetUserFTA.exe .mht ChromeHTML
SetUserFTA.exe .mhtml ChromeHTML
SetUserFTA.exe .xht ChromeHTML
SetUserFTA.exe .xhtml ChromeHTML
SetUserFTA.exe .svg ChromeHTML
SetUserFTA.exe ftp ChromeHTML
SetUserFTA.exe microsoft-edge ChromeHTML
SetUserFTA.exe microsoft-edge-holographic ChromeHTML
SetUserFTA.exe read ChromeHTML
SetUserFTA.exe ms-xbl-3d8b930f ChromeHTML
However, I found an article that in February 2023, Microsoft in the infinite wisdom changed Outlook’s behavior to always open every link from Outlook with MSFT Edge ☹…argh!!!
https://www.winhelponline.com/blog/outlook-hyperlinks-edge-default-browser/
In February 2023, Microsoft stated that for Outlook (365) and Teams, the hyperlinks will default to Microsoft Edge regardless of your default browser choice in Default Apps.
There is a way to override this thankfully.
Hope this helps those who are searching for way to change Outlook from opening links in Edge.
For those that use Edge and love Edge well just leave Outlook setting to use Microsoft Edge.