CrashPlan seems to like to tell me that backing-up is all done, even though it hasn't—and won't—done anything for days.
Their instructions involve:
/usr/local/crashplan/bin/./CrashPlanEngine stop then ./CrashPlanEngine startsystemctl restart crashplan should also work?
You'll probably have to manually kill some process/es. You should get error messages with the PID, otherwise ps aux | grep crash to find things.
Then use sudo kill {PID}
It seems to help if I just change some setting related to back-up frequency.