I am having the same issue. I ran the Vendor Open Balance report and figured out that one vendor had a check posted and a couple invoices were deleted which made it look like an over payment. I re-posted the invoices and re-applied them to the check and now it balances. However, I have another vendor that is off by $1.96. I ran the open balance report and it is not showing where I would be off by that amount. This is driving me nuts!