Invalid project file! Please Help!

Hello,
After 2 weeks working on a project file it suddenly becomes invalid and Cubase 10 won’t open it. What can I do in this case?
Please Help!

I am sorry to hear that you have trouble with your latest project.

Maybe these links help you:
https://www.steinberg.net/nc/en/support/knowledgebase_new/show_details/kb_show/troubleshooting-instructions-for-cubase-nuendo-and-sequel-on-windows#plugins