Fatal Error on importing FBX: parent != UnityGUID

Unity Engine
1

FBX import from C4D (R11 installed), Blender (2.48 installed) or source FBX files worked fine for me until just a couple of days ago.

I suddenly cannot import FBX files any more. I get thrown a Fatal Error reading “parent != UnityGUID”. The Model asset is created but is empty. This happens for any FBX file I try to import but only within one of my projects!
When I check the file size after the attempt in the Assets folder the file only has 4 Kilobytes in size (the file I drag&dropped in had around 1 megabyte).

What is happening here?
It only happes for one project! What can I do to fix this?

2

I don’t have a golden solution, just suggestions:

  • What’s unique about this one project or set of files? Finding that out might help you fix the crashing issues.

  • If this file (or files) were previously working just fine before then what have you changed since then? Roll back those changes and see if you get back to a working state, that will help you ID the problem areas.

  • Please log a bug immediately (Help > Report a Problem…) and include all relevant information and the model file(s) so we can look into this on our end.

3

I dug a little deeper on this one:

  • It only happens in this one project, if I create a new one, the import for FBX works fine there and I can import all files that won˚t work in the other project
  • It happens on ALL FBX files even if I try and import one of the FBX included in the Tropical Island Demo
  • There is no way for me to track back changes in the project. This happened for the first time 2 days ago, without me even trying to do anything model related, I just hit reimport on a character mesh by mistake and got this unfortunate result.

As it only happens in this one project I think the only way to report a bug would be to provide you with the whole project. The project has 12 GB at the moment, so I think that is no option!
I may be able to manage sending you a small version without textures - but I will have to look into that first.

I will try taking over all my assets into a new project - start fresh.