Great. Over a 1000 warnings & errors on opening a project in Unity 5.2.1 on my Mac that a colleague had updated from 4.6.8 to 5.2.1 on Windows. And all script references gone.
No such problem on my Windows machine.
Invalid metdata file discovered, no '.info' file. Will be deleted: 'library/metadata/00/00000000000000001000000000000000' and 'library/metadata/00/00000000000000001000000000000000'.resource (if exists).
Path mapping for Asset with GUID ba50d600348994f798c691e75a348ad2 is missing! Cleaning up.
Asset 'ProjectSettings/NavMeshAreas.asset' is in assets but has no assettimestamp...
Will have to delete and get again from SVN. It it happens again I’ll get a third time will send in a bug report before opening in Unity.