Vertical Tabs prevents Edge Canary 103.0.1250.0 from launching

There's an easy fix and a difficult fix. The easy fix is to uninstall and reinstall Canary to roll yourself back to an older version. We've pulled the build with this crash, so if you don't delete your user data when you do the reinstall, everything should just work.

If you don't want to do that, you can manually edit your preferences file to turn off vertical tabs. In your profile folder, open up the Preferences file and in the vertical_tabs structure, change "opened" to false:

Note that if you had vertical tabs in use in multiple profiles, you'll need to do that for all the profile folders, not just Default.  

Unfortunately, there's also a complication if you were restoring tabs from your previous session.  If the setting in edge://settings/startHomeNTP is set to open with your previous tabs, you'll need to temporarily be without them since session restore also restores this preference.  To do this, in the same folder as the Preferences file, rename the Sessions folder to something like Sessions_old, and then with those two edits in place, you should be good to go. We've already got a fix prepped for this, so tomorrow's Canary will be able to use the old session folder again. And in the meantime, hopefully something like your synced tabs from other devices will be able to restore some of your session temporarily, since the recently closed data in History is also part of the session, and thus will be blank since you're using a new session as part of this workaround.