This morning I saved a project as Conservation_Arts_6_12_2016 and closed out the software. Later, I changed the project file name to Conservation_Arts_Part_A and when I went to open the file I got the error messages: ‘Couldn’t find data folder’ and ‘Couldn’t open file’ (screenshots attached). So, I changed the file name back to Conservation_Arts_6_12_2016 but got the same errors when I tried to open the file.
You committed the cardinal sin of renaming the AUP file or _data folder. If you want to move or rename Audacity projects there is only one safe way, File > Save Project As… from within Audacity.