Often, a reinstall of Crashplan can fix issues like that too. I agree their use of Java is kind of crappy and leads to problems with the software, and I also agree that email notifications should be turned on to alert of any problems. It's possible to change the number of days before an alert or a warning.

But I mostly wanted to offer a little "FYI." The latest version of Crashplan finally has the ability to back up a network drive. Previously, I'd gone to a great deal of effort to install Crashplan directly onto my Synology as a headless installation, but the process was awful and the application kept stopping. It also kept me from updating the DSM for fear of breaking the Java/Crashplan apps.

Now, if you install Crashplan as a local user instead of the default system user, you can instruct it to back up any mapped network drive. I already have a laptop running at all times to control my home automation system, so I set that up as my backup computer. It was taxed for the first week as it backed everything up for the first time (Crashplan's adoption feature didn't work correctly), but after that it hasn't hurt my HA system.