We have two sage 50 accounts perpetual on two stand alone separate computers one for each of our small companies. One is still working OK the other has developed a message saying 'a licence for the supplied serial number cannot be found' The data (programe) version is v25.1.128.0 for both computers. We have current backups on memory stick. Tried uninstall programme and reinstall but the 2019 software installer will not upgrade when we reinstall it so backup files are not compatible. The problem cannot be anything to do with the September deadline 'security' problem as the one computer is still working OK. Kind Regards