I was not able to open my model that I worked on, since the model name has been changed to XYZ.erwin.1, which I was not aware of. Why did ERwin change my file name, and how can I open it using ERwin?
The file rename usually happens when an abnormal termination occurs while you are working with a model. The model might not have your updated objects depending upon when the model was last saved.
A suggestion would be to first make a backup copy of XYZ.erwin.1. Then, rename that as XYZ.erwin. You will then be able to open the model using ERwin and take a look at it to decide what you would like to do with it.
NOTE: a good way to merge changes from several models into one model is by using Complete Compare.