Since .mxd file are merely pointers to the actual data and symbol sets, simply sharing the file with users that don’t have access to the network the map file was created on is not a workable option. Users opening .mxd files on a computer that is unable to load the GIS data and symbol sets used, will find red exclamation (!) marks next to each missing dataset in the table of contents (…) Map packages are an easy way to create a portable file (.mpk) that contains the .mxd file and any referenced GIS data from the document. (…) The recipient can then simply double click the file to unpackage it and load up the file within ArcMap.
WHY DIDN’T I KNOW YOU COULD DO THAT.
The teachers were always asking us to send entire geodatabase+map file, why the hell didn’t they at least tell us about that alternative?!