Hi Akos, thanks for reply!
I did some digging and turns out older versions had both, header and footer, which made recovery much easier.
New versions only have a header 'ROF FDB', but don't have a footer. When this happens, usually the best way to recover these files is to follow header + max file size method. Meaning that the file originally could have been, let's say 100 mb. During recovery we indicate that the file could have been no more than 200mb. After that the recovery software starts pulling the data from hdd sectors beginning from the header and going until it reaches 200mb (100+100).
Now we get a file that is 200mb. Some programs can handle the extra data, but as far as I tested, ArchiCAD cannot. I'm getting an error that the file is corrupted.
Graphisoft, why you do this?