I tried using "Reinstall Fedora" (F41 -> F42 Beta) on 2 legacy BIOS machines, using the GNOME Workstation Live, and got the above error with each. (On one of them, which is Fedora only, and only a small amount of data in home, I worked around it by using "Use entire disk".) I don't see anything in Bugzilla, or in the RC-1.4 Test Matrix. I'm guessing this has to do with installing over an existing installation? I clean install each new version of Fedora and have never seen this error before.