Are you using Group By on a memo filed in your queries?
I did use group by... I made this query last year and there were no issues, till yesterday.
SELECT InvoiceFinalMain.CompanyName, InvoiceFinalMain.InvoiceNum, InvoiceFinalMain.Invdate, InvoiceFinalSUB.Product, InvoiceFinalSUB.Particulars, InvoiceFinalSUB.Amount, FinalTotalBill.TotalBill, InvoiceFinalMain.Chargedby, InvoiceFinalMain.Closed, InvoiceFinalMain.Preparedby
FROM (InvoiceFinalMain INNER JOIN InvoiceFinalSUB ON InvoiceFinalMain.InvoiceNum = InvoiceFinalSUB.InvoiceNum) INNER JOIN FinalTotalBill ON InvoiceFinalMain.InvoiceNum = FinalTotalBill.InvoiceNum
GROUP BY InvoiceFinalMain.CompanyName, InvoiceFinalMain.InvoiceNum, InvoiceFinalMain.Invdate, InvoiceFinalSUB.Product, InvoiceFinalSUB.Particulars, InvoiceFinalSUB.Amount, FinalTotalBill.TotalBill, InvoiceFinalMain.Chargedby, InvoiceFinalMain.Closed, InvoiceFinalMain.Preparedby, InvoiceFinalSUB.InvoiceNum
HAVING (((InvoiceFinalSUB.Amount)>0))
UNION ALL SELECT InvoiceAdvanceMain.CompanyName, InvoiceAdvanceMain.InvoiceNum, InvoiceAdvanceMain.Invdate, InvoiceAdvanceSUB.Product, InvoiceAdvanceSUB.Particulars, InvoiceAdvanceSUB.Amount, AdvanceTotalBill.TotalBill, InvoiceAdvanceMain.Chargedby, InvoiceAdvanceMain.Closed, InvoiceAdvanceMain.Preparedby
FROM AdvanceTotalBill INNER JOIN (InvoiceAdvanceMain INNER JOIN InvoiceAdvanceSUB ON InvoiceAdvanceMain.InvoiceNum = InvoiceAdvanceSUB.InvoiceNum) ON AdvanceTotalBill.InvoiceNum = InvoiceAdvanceMain.InvoiceNum
GROUP BY InvoiceAdvanceMain.CompanyName, InvoiceAdvanceMain.InvoiceNum, InvoiceAdvanceMain.Invdate, InvoiceAdvanceSUB.Product, InvoiceAdvanceSUB.Particulars, InvoiceAdvanceSUB.Amount, AdvanceTotalBill.TotalBill, InvoiceAdvanceMain.Chargedby, InvoiceAdvanceMain.Closed, InvoiceAdvanceMain.Preparedby
HAVING (((InvoiceAdvanceSUB.Amount)>0));