All you need is a SOLIDWORKS ID, or a new or existing 3DEXPERIENCE ID.
It's no secret that SolidWorks crashes a lot. But I'm finding in 2021 SP3.0, when changing configurations there's a 50/50 chance it'll just poof - disappear. No thinking about it, no crunching of numbers - just boom, SolidWorks completely goes poof.
(Am I doing the tag thing right for the new forum?)