If Red Giant Link crashes upon launch (or just crashes in general), it's possible that it'd gotten corrupted either during an update or during its initial installation.
- Uninstall the program
- Windows: Use your Control Panel's Add/Remove Programs to uninstall it
- Mac: Drag Red Giant Link into your trash from the Applications folder, then head to `/users/shared/red giant/` and trash the 'Link' folder there
- Reinstall using the latest installer here for Mac or here for Windows.
Should those two steps not work for you, contact support.