I'm working with ArcGIS 10.5.1, accessing an mxd file and geodatabase that are on a network server. Occasionaly the connection to the network is temporarily broken, and I get an error. When the connection is restored, unfortunately, ArcMap will not make any attempt to re-connect. Once it's gone, it's gone forever. You must close the app and lose all unsaved changes. Saving the map file with a different name is a workaround, but this shouldn't even be happening.
The worst part is if you are in an edit session. There is no way so save your edits. There is no way to even see any of the data you were editing, even after the connection has been restored! You must then lose all unsaved edits.
PLEASE fix this ESRI! There is no reason at all why this should ever happen!