-Please help- Client issue below and I don't even know where to begin Excel Ninja needed

(A trouble ticket was sent over to me... My co-workers tried for a month to resolve this and I have no idea where to begin)

I've never had this problem before, but I am working with Larry's spreadsheets and updating them with new data. It seems like it is fine when I link the worksheets from different workbooks, and even will be ok when I save/close and reopen. Then, for seemingly no reason (and without changing the location or name of the workbooks) it loses all the paths and the #REF shows up everywhere. This has happened multiple times now, and just when I think I have it figured out it happens again.

I did change the name of a workbook last night, hoping it would isolate it more from another workbook in a different folder with the same name. These are huge workbooks with many tabs so it is quite frustrating to lose all the data....again.

The one I have been working on recently is in M:\Business Financials & Tax Stuff\CFO\Financial Info\FY 2019\1-October Financials, which is (or was) linked to M:\Business Financials & Tax Stuff\CFO\Financial Info\FY 2019\Consolidated Financials 18-19 AND M:\Business Financials & Tax Stuff\CFO\Financial Info\FY 2018\Consolidated Financials 17-18.

Just when I think I have it resolved it messes up again. I don't want to keep trying things, having them work for a bit so that I have put much time into it again to just lose it all again. It's getting a bit out of hand. I'm stymied....I'm really hoping you can help! I have a board finance committee meeting today that I thought I was all ready for until 6:00 last night when it suddenly lost the data again!