Can't open .aup project file dating from 2010

Get an error message trying to open a .aup file in latest version of Audacity. Get an error message saying that the application doesn’t recognise the first .au file in the associated data folder.

May have to use an old version of Audacity … Managing Audacity Projects - Audacity Manual

Thanks for the prompt reply. I’ll try downloading a v. 2xx to start with.