Frequent crashes during the "Saving" process.
You won't get the lens profile updates or bug fixes required for new cameras. Color Efex Pro 4 Activation Key
If you have purchased the Nik Collection from DxO, here is how you activate it: Frequent crashes during the "Saving" process
If you are looking to get this legendary plugin suite running on your system, here is the current state of play regarding activation keys, free versions, and modern alternatives. The History of Color Efex Pro 4 Keys Color Efex Pro 4 Activation Key