There is a trick you can use to try to save a corrupt file. It often works, but it does not always work. The technique uses Workgroup Referencing to grab all the Design Layers, but you can not get any of the sheet layers, or sheet layer viewports.
If you have a backup, then you can open it and hope that it is OK to use. So, you need to set up the Vectorworks backup and you should have a backup strategy for your computer as well, to keep all your data safe.