Thanks for attaching these files, Tony. Dorico projects use zip compression, and the zip files for these projects are both corrupted. So the question remains: how did this happen?
Can you tell us something about the Macs in your department? Are they all the same configuration? What operating system(s) are they running? Are files saved locally or onto the network? If locally, are they saved onto an internal or external drive? If on the network, what network protocol are you using to connect to the network volumes (e.g. Samba? AFS? something else?), and what operating system is the network storage running? What filesystem is the network storage using? Finally, how were the files copied from one machine to another? Were they transported on a USB flash drive, or similar? If so, what filesystem is the USB flash drive using?
Can you open other projects without problems? E.g. if you create a new project, save it, close it, and reopen it, does that work? Try opening one of the Dorico example projects (from /Users/Shared/Dorico Example Projects), and then doing Save As to save it somewhere else, then close and reopen it again: does that work?
The peculiar thing about these projects is that although the zip files are too corrupted for Dorico to be able to open them, macOS seems to be able to recover them OK. See if you can do the following:
- Change the file extension of one of the corrupted projects from .dorico to .zip. Answer in the affirmative when asked if you want to proceed.
- Double-click the new .zip file to uncompress it.
- You will end up with a folder called e.g. ‘GRASSBY viola piece’, inside which are two files (score.dtn and scorelibrary.dtn) and two folders (META-INF and supplementary_data). In the Finder, select these two files and two folders directly, not the parent folder.
- Right-click on the selected files and folders and choose Compress 4 items from the context menu.
- Change the filename of the resulting ‘Archive.zip’ file to e.g. ‘test.dorico’. Again, answer in the affirmative when asked if you want to change the file extension.
Now try opening the test.dorico file you ended up with in step 5 on your Macs. You should find that it opens as expected.
Hopefully with some answers to the questions above we’ll be able to get to the bottom of this problem.