I was wondering if there was a way to make it so that multiple people could view a map at the same time without having to come into contact with the dreaded red !. Currently the data and .mxd file is stored on a communal server and everyone has access to the file and data but when one person has it open and another opens it, the red ! comes up.
Is there a way to "share" the file, like when an excel spreadsheet can be shared among multiple people? or perhaps a mode where it is "read-only"?
If mxds are saved with the 'relative paths' toggle used in map document properties. Then a project should open as long as the mxd is located 'relative' to the data paths. If the mxd becomes disjoint from the data, then the ! marks will appear. Perhaps you might want to look at 'Packages' as an alternate way of sharing a project and its data.
You can share the map documents as a published map file aka .pmf
You need to have Publisher Extension for Desktop. In this way you can share the data with Read Only capabilities. Once you have created the pmf file you need to install ArcReader on the machines where your colleagues need to open them. ArcReader has to be of the same version as ArcGIS Desktop which was used to create the pmf in the first place.
Be aware that data types in a map can cause issues. Specifically, excel data when added will create a lock file, preventing you from having more than 1 person accessing it at a time. This will cause errors when you have a map open with a pointer to that file, and a second person attempts to open that map document. Solution: use a different file format, such as shapefile or feature class.