how get one account from past backup but not all the rest of the accounts.

Hello @Chuck Gray

Thank you for taking the time to visit the Community to report this issue, although I apologize that you have not received a response.

I would navigate to the file that contains the one account that you would like. I would then save a backup. I would then remove all of the accounts save for the one account in Quicken. 

I would then navigate to File > File > Export Quicken Transfer Format (.QXF File) I would then save this file to the desktop or somewhere that it is easy to find.

You will then navigate to the current file and navigate to File > Import > Quicken Transfer Format (.QXF) File... then select the QFX.

This will transfer the one account into your current file.

Please let us know how it goes!
-Quicken Tyka