Following- I have a similar problem

We have something similar in AP....invoices from 20+ years ago showing outstanding on reports but you can't delete, change or even pay to get them out of AP.  Talked with Sage a couple years ago and they stated that it was something corrupted in our data and for a large fee they could make it go away.  We have just chose to deal with it, even though it is a Sage issue. 

Following for more info-

We have it on AR and AP with old retainage lines that have been invoiced but wont clear to $0.00 and stay on aging forever.I guess we all have the same corrupted data?

I guess so.  Never Sage's fault ;-)

I've got one from back in 1998! I just put the invoice on hold and ignore it (although it still irks me every time I see it).

 Plus the vendor's been long gone out of business, but I can't delete a vendor with an "open" invoice.

Funny.  Our oldest is from 1998 also that we can't get rid of. 

I finally got mine to clear by running 3 separate zero dollar checks. 

Mine had 3 invoices for a vendor at -0- in AP. But it shows up in AP as open invoices with a zero balance. When I select them for payment and amount shows up to be paid.

I selected to pay the 3 and entered an invoice to offset that amount (posting to our cash account) Cut the check which will zero out the cash account invoice I used to reverse. 

Once I did that it still showing up in AP as open at zero.  

Selected for payment again and the amounts it showed, entered another offset invoice. Cut another zero dollar check.

It was still showing in the open invoice selection window at zero. But once I selected to pay an amount showed again. Cut another zero dollar check.

Now all are gone. 

If you have old Invoice that wont seem to clear you can connect with Sage professional services.  They can take you data and fix it.  Very fast and easy. Contact at [email protected]