Invoice/Estimate List is Full

I am using Reckon Home and Business 2016 (Desktop version), and have been using Reckon products for more than 20 years, but today I am stuck.

When I attempt to create a new invoice I get the message "The Invoice/Estimate list is full.".

I have traditionally not done year-end copies etc so that I can do long term reporting/comparisons etc. but found after reading the community support forum that the only way to fix this problem was to do a year-end copy. I did this and my transactions were reduced to the date specified but the invoice list was not! I have also tried a file copy with a reduced date range but that also reduced the transactions in the file but not the invoice list. How do fix this problem?