Remember: An ArcMap document (mxd) does not store spatial or attribute data. It stores path names to your GIS data layers. A path name is the "address" of a file or folder on your computer, and includes the drive, folders, subfolders, and the file name.
In order to make your map portable, for instance to share it with a colleague or to archive it for a later use, you need to keep the data and the map document together in the same relative positions in your folders. You also need to save your map document with relative path names.
To make a portable map document from scratch:
1. Assemble and organize your data in a single project folder. If you have lots of layers, sort them in separate folders by data type or geography.
2. Make your map in ArcMap by adding data from your project folder.
3. To be sure all the data in your map is in the same project folder, click the Source tab at the bottom of the table of contents. The layers will be listed under their paths.
4. In ArcMap, choose File> Map Properties or Document Properties (depending on the version of ArcGIS you are using)> Data Source Options. In the Data Source Options window, choose Store relative path names. Click OK.
5. Save your map in your project folder.
6. Now you can move the map by moving the entire project folder.
How to repair a "broken" project.
If you open a map document where links to data are broken, your layers will not draw in your map and the layers will have small red exclamation points next to them in the table of contents. You can repair the map IF you still have the data layers available.
1. Copy all the data to the proper folder using Windows Explorer, ArcCatalog, or the export data function in ArcMap.
2. In your broken ArcMap document, click on the red exclamation point next to the missing layer in the table of contents.
3. Browse to the layer in the project folder, click on it and choose add. Repeat this step for every broken link.
4. The red exclamation marks should disappear. If the layers fail to draw, try clicking the refresh button to redraw the map.
5. Save relative path names as shown above.
This project is stored properly with the map document and the data layer stored in the same project folder. The map document is saved with relative path names so it will open anywhere, as long as the states shapefile is in the adjacent "shapes" folder.