Thanks for creating new thread on this Cathy.
Does this appear for all the workbooks or is it happening only for the "CalculationFrustration" workbook. I tried to open and close multiple workbooks and i can get access to recent workbooks appear in tableau desktop recent files section. The challenge here would be to replicate this issue. Are you able to replicate this issue other than "CalculationFrustration " workbook ?
Yes, it's definitely happened with more than one workbook. What I haven't done, yet, is to take the time to determine if it makes a difference where the file is saved, i.e. a network drive, my hard drive, my desktop, etc. That's the only difference I can think of that might matter.
I just created a workbook and saved it 3 different places and both as twb and twbx and could not replicate it. But when I opened one of the files I was having trouble finding (not CalculationFrustration) and altered it so it would show it was recently changed, it still didn't show up in Tableau's recent list even though if I use Windows Explorer it said it was just modified. Not sure what rabbit trail to chase next... :-/