How do I remove an app folder is OSX when all else fails?
I jumped a gun posting here and got the answer elsewhere.  Here is the solution:
Because uninstall has already failed, the problem may be that the "system immutable flag" is set for /Applications/CrashPlan.app or its contents. In Terminal, try 

ls -ldO /Applications/CrashPlan.app 


and 

ls -ldO /Applications/CrashPlan.app/Contents


The ls command may show something like this:

drwxrwxr-x@  3 root  102  schg   13 Jul 14 20:36 CrashPlan.app


If you see the schg flag, run these commands:

sudo chflags -R noschg /Applications/CrashPlan.app
sudo rm -fR /Applications/CrashPlan.app