How can I protect the data from being changed?

Method 1: Lock the collection by selecting it and then choosing Lock Collection from the Data menu. Users will not be able to change the data unless they use the Unlock Collection command.

Method 2: Lock the document itself using normal Windows or Mac operating system procedures. Users will still be able to change the data, but changes they make will not affect the saved document.

The sample documents that come on the Fathom CD are locked by default.

Also remember: When data is changed, you can use Undo until the data is back to its original values, or you can use Revert Collection in the File menu to return the data to the values it had the last time it was saved.