Mailmerge/label DB problem

[NWSailor]

First, I hope this is a good spot to post this question, if there is a more appropriate forum, please let me know. I'm pretty experienced with spreadsheets and have successfully mailmerged in the past but I am less familiar with databases. Here is the issue:

I have a spreadsheet named “Members 2019” with names, addresses and other data kept in a folder named 2019. Last year in January I successfully completed a mailmerge to create address labels from this spreadsheet. This January I created a new folder called 2020, I then made a copy of the spreadsheet in the 2019 folder and put it in the 2020 folder and renamed it to “Members 2020” Since last January many changes had been made to the speadsheet data. I like to keep annual copies of previous information because occasionally I need to see the history of changes over the years.

When I open my Members 2020 spreadsheet and start to mailmerge for labels, older data from the 2019 spreadsheet is in the database that was created for the label mailmerge. Where I come to an impasse is at the dialog box that pops up after selecting New > Labels. It seems that the mailmerge/label process is accessing a database that was created from the 2019 spreadsheet.

What is the best way to solve this problem? Delete the old database? If so, how do I create a new one that the 2020 mailmerge/label process can access?

I hope all of this has been clear, I probably don't understand exactly what is going on and would appreciate your help in understanding and solving this problem. Many thanks for your input and help!

[Villeroy]

Wrong approach. You must not split equally structured data in separate table, separate sheets, separate files, let alone separate folders. This is always a mistake.

Nevertheless, you can easily change the source sheet of your mail merge document. Just open the registered Base document, call menu:Edit>Properties>Database... and change the spreadsheet that is linked to that database.