Disappearing X References

I have been having a problem for a while with Xreferences disappearing from the drawing when bound, yet they still show up in the XRef Manager. I have noticed that if I unload they reference then reload it; it will show up again where it belongs, all the same, it will not bind.

I have heard lot's of explanations. The one I tend to go with is that there are duplicate blocks in the two files preventing the bind mid action leaving you with no visible reference.

Here is a list of possible fixes. Start at the top and work your way down. They get more bothersome as you go, but I haven't missed getting it to work eventually yet.

1. Right click on the referenced file and pick Open Xref. Make some change like zoom extents, save and close. Reload when prompted in the original drawing then bind.
2. Purge both drawings.
3. Recover both drawings.
4. If the referenced drawing has attached references, change them to Overlay and bind individually.
5. Detach the reference file, purge and insert as a block.