Sometimes when I open up Scrivener, I get a message along the lines of “this project is already open on another machine.” I close the error box and continue. Although I have Scrivener on my laptop and a desktop machine, they are not networked, neither do they have a wifi connection. Baffling.
Please read the full message:
So given that you don’t have it open on another machine, it must not have been closed properly. This can happen if the program crashed for some reason, or if you somehow quit Scrivener in a strange way. It might also happen with older projects that need updating - for instance, I believe that if you create a new project from a 1.1x template, you would get this message; if that’s the case, you just need to update the templates to 1.5x by re-downloading Scrivener from the product page and just re-installing the Extras.
All the best,