Project not opening

I am getting an awful lot of video service crashes and general Nuendo freezes at present.

After one such crash, my current project will no longer open if I double-click it in the Finder with Nuendo not running (i.e. double-clicking the file opens the application). It crashes Nuendo on loading.

If I open Nuendo first, then open the file from the open menu, it seems to work. But is this project corrupt somehow?