Hi Jeremy,
While mapping objects, TestComplete can store information about methods and properties of the objects. The stored information makes it easier to modify tests and add new test operations: you will be able to see the list of object methods and properties in keyword test operation editors and Code Completion even if your tested application is not running at the moment.
To specify the level of the details to be stored, you can use the Store Code Completion information option. If this option is set to Full, TestComplete will save the complete list of methods and properties of the objects that will be added to Name Mapping. It can be useful when developing new tests. However, this may result in a large size of the Name Mapping file (as in your case) and, therefore, large memory consumption by TestComplete. To avoid the issue, use the Brief or None option instead.