Sometimes when installing or uninstalling software that shares common system files with Legacy problems can arise. For example, when installing another program, a different version of a shared system file may be installed. In addition, when uninstalling another program, a person may say "Yes" to the prompt about deleting all shared files. As a result Legacy no longer runs properly. In addition over time, computer files can seemingly become corrupted on their own -- possibly due to improper computer shut down or system problem.
If these steps don't solve the problem please contact Support@LegacyFamilyTree.com with the details of the file you need replaced.