Recently I ran into an issue syncing my iphone 4 with my OS X Snow Leopard iTunes. When I would attach the iphone, IÕd get:

iTunes was unable to load data class information from Sync Services. Reconnect or try again later.

The fix was to reinstall iTunes directly from Apple

Download iTunes

So I've joined the 21st century and started using a cloud based backup solution. I went with CrashPlan and have been very very happy with it. I have it backing up a tad over half a million files using 1.2 TB. It ran for weeks just fine, backing up happily to the cloud, but one day the client refused to launch. It would hang or sometimes say "Unable to Connect to the Local Backup Engine". I restarted, rebooted, and reinstalled, but nothing worked. I finally found the error log at /Library/Logs/CrashPlan/engine_error.log and it had this:

Exception in thread "W1995120947_BQTaskWrk-42" java.lang.OutOfMemoryError: Java heap space
Exception in thread "Sel-Peer-R" java.lang.OutOfMemoryError: Java heap space
Exception in thread "QPub-BackupMgr" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W1294712427_BQTodoWkr-42" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W1784681719_SpotQW" java.lang.OutOfMemoryError: Java heap space
Exception in thread "Poller SunPKCS11-Darwin" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W2018078818_NIWatcher" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W469605589_PeerTimeoutWrk" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W1810844459_BackupConnWrk" java.lang.OutOfMemoryError: Java heap space
Exception in thread "DMORcvW-sId...6258" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W702703106_RPCtdWrk-DefaultGroup" java.lang.OutOfMemoryError: Java heap space
Exception in thread "RPConnWrk-DefaultGroup" java.lang.OutOfMemoryError: Java heap space
Exception in thread "W1680293710_SFQ-CW-1" java.lang.OutOfMemoryError: Java heap space
Exception in thread "Thread-2" com.code42.exception.DebugRuntimeException: Unable to persist ServiceModel, Java heap space
    at com.backup42.service.model.ServiceModel.save(ServiceModel.java:173)
    at com.backup42.service.CPService.cleanup(CPService.java:1400)
    at com.backup42.service.CPService$1.run(CPService.java:253)
Caused by: java.lang.OutOfMemoryError: Java heap space
        

Hrm. That's not good. After a bunch of research, I found out that by default crashplans limits the java memory heap to 512 megabytes. I know I have a ton of files and need more, so after some more research I found that you can edit the maximum memory in /Library/LaunchDaemons/com.crashplan.engine.plist

There is a line that looks like this

-Xmx512m

and I changed it to this

-Xmx2048m

and now crashplan has been happily running, backing up my files.