CrashPlan cache getting too large on Mac OS X

This article helps you to clean up the cache directory that CrashPlan uses to storage its metadata.  Apparently CrashPlan does not clean up it’s own cache files in an effective way at this point on Mac OS X. The “cleanest” way is to just uninstall and reinstall the application however sometimes you don’t have the time for this so try this out.

Symptom:  /Library/Caches/CrashPlan directory or /Library/Logs/CrashPlan/engine_output.log is taking up several GB of space and just growing (5+ GB of space).

Solution:  Setup new cache files and remove the old cache.

Here is how you do it:

Open CrashPlan: [(CommandKey) + (SpaceBar) and type: “CrashPlan”]
Double click on the CrashPlan Logo in the upper right corner (looks like a green house).
A command window (below) will open up.
Type “backup.replace 42” into the command window.

Now it is time to shutdown CrashPlan, remove the old cache files and then restart the process.
Open up a Terminal window [Press (CommandKey) + (SpaceBar), then type: “terminal”]

Shutdown the CrashPlan process:
My-Mac:~ username$ sudo launchctl unload /Library/LaunchDaemons/com.crashplan.engine.plist
the cache files:
My-Mac:~ username$ sudo rm -r /Library/Caches/CrashPlan/*
My-Mac:~ username$ sudo rm -f /Library/Logs/CrashPlan/engine_output.log
the CrashPlan process:
My-Mac:~ username$ sudo launchctl load /Library/LaunchDaemons/com.crashplan.engine.plist

Use this command to view if the engine is running:
My-Mac:~ username$  ps auxww | grep -i CrashPlanService

The output will look something like this:
root        63   0.1  6.1   873644 126976   ??  SNs  Tue03PM  43:01.37 /System/Library/Frameworks/JavaVM.framework/Commands/java -Dapp=CrashPlanService -Xmn10m -Xms15m -Xmx512m -Djava.awt.headless=true -Dfile.encoding=UTF-8 -Dnetworkaddress.cache.ttl=300 -Dnetworkaddress.cache.negative.ttl=0 -DCP_USER_NAME= -DCP_USER_HOME= -cp lib/com.backup42.common.jar:lib/com.backup42.service.jar:lib/com.code42.backup.jar:lib/com.code42.bplusj.jar:lib/com.code42.messaging.jar:lib/com.code42.os.jar:lib/com.code42.peer.jar:lib/com.code42.utils.jar:lib/com.jniwrapper.jniwrap.jar:lib/com.jniwrapper.macpack.jar:lib/com.jniwrapper.winpack.jar:lib/jtux.jar:lib/trove-2.0.1.jar:lang com.backup42.service.CrashPlanService

Now you should be good to go and the cache file should grow over time.  You may need to do this once a quarter or so.

I gathered this information from two websites: and