Cannot Duplicate Project

This morning I received notes on an edit and went to duplicate my project so I can make the changes and was presented with the following error: The operation couldn't be completed. No such file or directory

I'd never seen this error before, and figured "oh maybe something weird happened to my library file" so I just made a new library, copied everything over and tried again. Same problem.

To further troubleshoot I made a brand new library, that was completely empty, and just made a dummy project: no contents, just an empty timeline. Went to duplicate it and got the same error again.

I tried trashing my preferences: same error.

I tried deleting and re-installing Final Cut: same error.

So this command just straight up doesn't work now, and I'm afraid to do any more work in case there's more problems coming my way. So needless to say it's a pretty crippling bug.

What is your system drive's capacity?
How much is left as free space?
Where is your Library stored?

If your library is on an external drive, make sure that drive is formatted as OSX Extended Journaled and not NTSF. There have been issues with libraries stored on NTSF formatted volumes.