Hello David,

It gets there if an integer identifier of diagram element class is not recognized. We haven't been using these identifiers for new classes since a long time but use the RegisterItemClass method instead for newly added types, and the load code would throw FileLoadException if the class id is not recognized. So this does not sound as a version compatibility problem, but either the file stream current position is wrong or the file is corrupted.

We are not aware of anyone getting corrupted files in normal circumstances, maybe check if the file wasn't saved on a full disk, or over slow/unreliable network - that might have cut off the file or thrown some exception.

For the other possibility - wrong stream position - if you use any custom node types, or handling serialization of DiagramItem.Tag or ControlNode.Control instances, ensure your code always reads as many bytes from the stream as it writes. If you believe the problem is in our serialization code, please attach the file for us to inspect.

Regards,
Slavcho
Mindfusion