I enabled this last night and it deleted my existing profile, fwiw.

Both bookmarks that I'd just created and, just to clarify I'm not losing my mind, the full profile because I had to reinstall ublock origin.

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Anthony-G 5 hours ago | parent [-]

After shutting down Firefox and restarting, I tried the new profile manager UI just now and also thought I had lost my existing profile. Luckily, it was still available from the hamburger menu (just below the “Synchronise all your devices” option) and I was able to switch back to it (with all my existing bookmarks, containers and extensions).

	▲	x0x0 4 hours ago \| parent [-]
		I'm glad you found yours, but mine was gone. I went spelunking through the profiles directory and it was nowhere to be found. I had to pull it from backups.