Can't even write lock the .plist.
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brandenm
OP here. I'm also willing to help track it down.
As a workaround, I've tried removing all write-permissions from my /Users/jeerobair/Library/Preferences/org.forkit.MacBiff.plist, but despite it's being owned by me, MacBiff will over-write it anyway (at least, whenever I do a manual Save).