If you can still rotate and zoom in on the part, it sounds like there may be some non-modal dialog popping up, but off screen, but I'm uncertain of what non-modal dialog may be coming up in the save process. To confirm that there is in fact a dialog popping up, you can try hitting ESC to see if that dialog closes and control comes back as normal. This won't definitely confirm it because ESC does not close all dialogs, but it does for most. You could also try Alt-tab to see if you can see the dialog in that screen and switch to it. Or, you can look in the Windows task-bar and see if there is an icon for it and then press shift and push the right mouse button on the icon and select move and use the arrow keys to see if you can move it onto the screen.
I hope this helps,
This worked out, thanks for your help. Pressing escape did allow me to return. Turns out after I upgraded to SW 2018 it was asking me to save my old outdated files as 2018 files in a pop-up off screen. I still can not find the dialog box when things seem frozen but I realized this was the issue the after the couple times it did appear correctly. Thanks!