Is this some Bug or the Project has gone corrupt ??

I have been working on the development of a VR project for about two months or so.
The build with version 4.9.2 went fine as usual.
It was well tested, packaged and deployed.
Now i wanted to make changes to the project and here are some things that are happening.

  1. The lighting does not build anymore. Stays at 0%.

  2. I can’t package the project anymore. To any of the platforms!!

  3. I don’t see the ‘plugin’ option anymore, in the Edit menu.

There might be many more issues, but these are the ones that i have come across for now.

Why has this happened?? Is this a bug or somehow my project has gone corrupt.
In between i had taken some actions.

  1. I updated OSX and Xcode.
  2. I downloaded 4.10.
  3. I cloned the project to migrate/update it to 4.10.
  4. The cloned and switched project behaved in the similar manner, traits similar to the ones i listed above.

Can someone suggest, what has gone wrong?
How can i get back to working with the project?
Is there anyway that i can recover the project?