You cannot void partially paid transactions" in Sage 50 cash-basis VAT
Sage 50 blocks voiding a partly paid invoice or bill while cash-basis VAT reporting is on, because the VAT already claimed would be reversed.
Sage 50 is telling you a hard rule, not reporting damage. The message reads:
While cash-basis VAT reporting is being used, you cannot void partially paid transactions.
In plain terms: the invoice or bill you are trying to void has at least one payment or credit applied against it, and your company uses the cash basis for VAT. Sage 50 refuses to void it because voiding would erase the payment history that determined when VAT was actually claimed.
Why cash-basis VAT makes voiding impossible?
Under the cash basis, VAT is claimed when money changes hands, not when the invoice is dated. A partially paid transaction has two VAT stories: one for the paid portion and one for the open balance. Voiding the whole document would collapse both into nothing, and the VAT you already reported on the paid portion would no longer match your filings. Rather than let the books drift out of line with the VAT return, Sage 50 blocks the void outright.
This is a deliberate constraint, not a bug, and it applies only to transactions with payments applied. A fully unpaid invoice or bill can still be voided normally.
Can you delete the payment first?
Often, yes. If the payment itself is wrong, void or delete the payment first. Once the transaction has no payments applied, the void option should become available again. Work in date order and check your VAT return period before you do this. If the payment fell in a VAT period you have already filed, reversing it now creates an adjustment that belongs on a later return, and you should note it for your accountant.
Be careful with linked documents. If the payment came from a customer receipt or a vendor payment that covers several invoices, removing it affects all of them. Review what is linked before deleting anything.
What if the transaction is simply wrong?
If the amounts or details are wrong but the payments are correct, voiding is the wrong tool anyway. The cleaner fix is to adjust the open balance: apply a credit, record a correcting entry, or issue a credit note against the remaining amount. That leaves the paid history and the VAT already claimed intact.
If the whole transaction should never have existed, the usual approach is to void the payments, then void the transaction, then re-enter whatever was real. Do this inside the correct VAT periods where possible, or record the resulting adjustments.
When the file itself is the problem
A separate situation: sometimes users report this message on a transaction that appears fully unpaid, or the void option stays greyed out after every payment is removed. That pattern suggests the payment links inside the data file are damaged, so Sage 50 still believes the transaction is partially paid. This is a data problem, not a VAT rule, and it will not resolve by retrying.
Our engineers repair damaged Sage 50 and Simply Accounting databases, including broken transaction and payment links. If you suspect that is what you are seeing, we offer a free evaluation of the file before any work is agreed. You can also read more about our Sage 50 database repair service or send us the file for a no-obligation assessment.
A practical next step
Before anything else, open the transaction and list every payment and credit applied to it. If the list is empty and the message still appears, stop retrying and have the file looked at, because each failed attempt adds nothing and the underlying link damage will remain.