Thanks @PinkElephant
I do have access to both personal and work computers (laptops).
But the other assumption isn't quite true. I admittedly have a complex setup. Two Evernote accounts, personal and work, each associated with their corresponding email. I already share a few notebooks from my work account to my personal account, so I can work from either computer. But the personal notebooks on my personal account are meant to never be on my work computer, obviously. During an Evernote upgrade on my work computer, I got logged out. The problem started with I inadvertently logged into my personal account from my work computer, and happily went into the usual work notebook (since it was a shared one, no surprise, nothing to immediately alert me to my mistake!). Meanwhile, Evernote happily sync'd all my personal data onto my work computer.
I could just delete all my Evernote stuff, remove the app, etc., on my work computer. Then reinstall it fresh and only log into the work account. It's just that there's a lot of stuff, like 5 years of stuff. (My personal account goes back much, much further, and it's easily 10x as big.)
I just thought I could circumvent, take a short cut, after I logged out of the personal and into the work account (from my work computer). In theory, that non-active folder should no longer be needed. But, you know, like you said, it's messing with the database in a way, and that could blow its mind.