Hi Dharma Rajan,
Please note: an MXD is a map document showing data from one of more Feature Classes in a particular setup.
If you start an edit session (with Start Editing), you are not editing the MXD in itself, but the underlying data in one or more of the Feature Classes. This is an important concept in GIS, which you have to understand: there might be cases that your map document (i.e. the MXD) did not change at all, but where the content of the map (i.e. the data you are looking at) has changed because the underlying Feature Classes have been edited.
So,
- to protect your MXD: make sure that the *.mxd file is stored in a location on your file system where users can access it in read-only mode. This will avoid the MXD accidentally being overwritten...
- To protect the underlying data: make sure the permissions to edit the Feature Classes in the geodatabases are set correctly.
A more general consideration is: why would you use an expensive desktop product (like Arcmap10.6.1) as a simple viewer? Wouldn't it be more easy and flexible to share your geodata through ArcGIS Online (or Portal for ArcGIS), depending on your needs and the audience you want to reach? You could consider to build your own custom web mapping application using the ArcGIS API for JavaScript, to allow your users to view the data in a web browser of their preference (e.g. Firefox - or at least that would be my choice...:-)).
Please let us know what you think.
Best regards,
Egge-Jan
