CrashPlan PROe provides “continuous backup” that’s different from other, more traditional backup applications. Rather than kick off a resource-intensive backup session once or twice a day, it's much more lightweight and unobtrusive.
CrashPlan PROe uses your computer’s built-in notification system to learn about changes to your data. It listens to your operating system to learn when files have been added, removed or modified. It queues up the eligible files, then compresses and encrypts the data prior to sending them over the network. This happens every fifteen minutes by default.
Just to make sure no files were missed, there is a once-a-day disk scan to account for any changes that might have been overlooked. This usually happens around noon each day. If your computer was turned off, that scan will take place later in the day.