Error opening file

I created a file in Dorico 1.2 on the 19 Dec and worked on it again on 20 Dec. Today (28 Dec) I tried to open it again and was greet with an ‘Error opening file’ message. Furthermore, the opening hub screen shows ‘my’ ‘recent projects’ to be 7 projects I did not create and have never opened (including Rameau and Coldplay files), and it no longer shows any of the files I did create myself and have opened recently. Also, when I do open up another file (which can open successfully) I now get tutorial-style windows explaining the basics of a software I’ve been using for more than a year.
All of this is not connected to the 1.2 update, since I did that on 6 December just after it was released, and used Dorico several times since then (including creating the currently-unopenable file).
Is there an easy solution to this problem? (The main problem is the unopenable file; the other information is merely context in case that assists in identifying the source of the issue - I have already turned off the tutorial windows and am successfully ignoring Coldplay).

It sounds as if all of your application preferences have been reset (which is why you are seeing the default example projects in the Hub window, and you’re seeing the guided tour when you visit each mode as if for the first time again). This could have happened if you downloaded and ran the clean-up script linked from the FAQ thread (though I guess you would have said so if you’ve done this), or if you’ve done something significant to your computer, for example you’ve switched to a different user account, or you’ve restored from a backup that was created after installing Dorico but before running it for the first time.

As for the project that can no longer be opened, please zip it up and attach it here so we can take a look and see what happened. My suspicion is that you may have had some kind of fairly serious issue with your computer – indicated by the fact that all of your preferences have been removed – and the file may be unrecoverable, but if you attach it here we can see. You should also check the ‘Backup Projects’ folder inside your ‘Dorico Projects’ folder to see if a backup of the project is found in there.

Thanks Daniel (especially considering the time of year).
I have not done anything particularly odd with my computer (a Mac running Yosemite), but I did have a space crisis this week, resulting in me deleting a lot of iOS backup files. I wonder if there was an error in saving because of lack of hard drive space when I saved the file last week? would that have affected Dorico’s preferences?
I’ve attached the file. It’s not particularly large or long, so rewriting it won’t be a chore if it can’t be salvaged.
Thanks for your help!
goodbye my (168 Bytes)

I can tell even without downloading the zip file that the file is incomplete: the zip file is only 168 bytes long, which means that it cannot possibly contain a complete Dorico project. Did you find any workable backups in the Backup Projects folder?

Thanks. I found the backup folder and there were some backups in there. I’ve lost some edits but not the whole project. Thanks for the assistance!