@BratAtTbredMgmtGrp You have my condolences; I've had to fix a few things like this, and it's never easy, and rarely the same processes involved.
A good starting point may be to look for 'Forced Reconciliation' entries, where whoever handled it before forced the books to reconcile despite discrepancies.
Past that, I'd say your course of action depends in large part on what kind of company you're dealing with.
For instance, if it were a sole proprietorship (Unlikely, since you mentioned it was a large company), it'd probably be easiest to simply start a new file as of the start of this year, though there's a lot of possible complications even with that kind of company.
If it were a sole proprietor and you opted to keep the old file going, I suppose you could use an Equity account to bring the bank accounts to balance at the start of the current year as well; Sole proprietors have a much simpler Equity system to track than, say, S Corps. It's just money taken out/put in, and the Retained Earnings rolling over from year to year... basically.
In all likelihood, though, it may be best to consult a CPA if for nothing else than advice. There are smart people here, but they also can't see your books in real time even if you wanted to share them with strangers.
(Also, for reasons you're no doubt aware, keeping hard copies of the bank statements would be a great idea going forward. Banks are so stingy with those.)
