spontaneous overnight hard drive wipe ???

Western Digital's "SmartWare" and "Drive Utility" software will erase hard disks. Remove those programs and do not use them, or any similar "utility" software from other manufacturers.

Most likely, your disk drive is fine, but the data is probably gone. Despite having had many months to prepare and test their software for Mavericks, Western Digital is predictably blaming Apple, but I have a variety of WD hard disks as well as others used in Time Machine applications and have experienced no data loss with any of them. Make it a habit to discard any "utility" or "monitoring" software or similar free junk comes bundled from disk drive manufacturers. It's not required and often causes problems.

I don't know where WD hides its potentially troublesome components, but be sure to verify for yourself that they are not present on your Mac. There is a long discussion about this problem in the following: Mavericks corrupts external hard drive Merely erasing WD's components, should you find any, will not resurrect your data.

You may have to navigate your way through an objectionable amount of noise to find a few gems of insight.

I haven't read every page of that sordid Discussion but in case anyone suggested doing so, do not use any third party "cleaning" apps to uninstall anything. That will only compound the problem.

Always highly recommend to reformat new hard drives to erase proprietary software pre-installed.

Western Digital in particular. I will add not my first choice in external harddrives.

Starting your Mac in "Safe Mode" will allow you to uninstall it and any other Western Digital utilities. Read about it: Starting up in Safe Mode

Disconnect the drive first.

wdhelper is not related to Western Digital. It's required by OS X.

Thanks to some info on the : Mavericks corrupts external hard drive discussion board I found some Western Digital software on my iMac I never knew existed. I never installed this, it wasn't in my Applications folder and it never showed up in a spotlight search but lo and behold there it was in:

/Library/Application Support (WDDriveManager)

/Library/LaunchDaemons (com.wdc.drivemanagerservice.plist)

I ran the WD uninstaller software - http://support.wdc.com/product/download.asp?groupid=124&sid=214&lang=en which removed those particular files and then I manually deleted the uninstaller pref file which appeared in /Library/LaunchDaemons after running the uininstaller.

I suggest that you contact both Apple tech support and WD tech support and report the issue. I currently have an open case with Apple and they are 'working on it'. WD are supplying customers with a license key for data recovery software, so hassle them. I was advised (by Apple) not to do anything to the affected drive just yet. So it's up to you if you want to go ahead and try and recover the data using software. No guarantees it will work of course!

My advice would be to run the WD uninstaller, uninstall Mavericks and roll back your OS, contact both Apple and WD with details of the problem and double up on your back up routine. I personally had most of my affected data backed up, but not everything.

Several things I used to do I will no longer do. Those include being slack with my back ups and leaving drives permanantly plugged into computers, even if the drives are switched off at the mains! Never do I install software bundled with hard drives, so I am at a loss as to how those WD files got on my machine. From now on I'll be making sure any HD with Data on it that gets plugged into my computer is already backed up.

The referenced discussion is important to read through, as it's the most thorough on this topic.

I had the same problem happen.

Your data is highly likely to be there. I used Data Rescue 3 to recover literally all of my data.

Problem is, the file structures are gone and lots of it is disorganized.

Step 1 - remove the WD software completely

Step 2 - recover the data with a non-repairing, non-invasive tool (like DR3 or Disk Drill, which is also said to work)

Step 3 - there appear to be some ways to try to get the now "empty" (it's not) drive to show the files again - check the long discussion to be sure.

ProfessorP wrote:

Since my drive in question was just a time machine backup I simply reformatted it and did a clean install of Mavericks.

It is important that you make sure the WD Utility software is no longer on your Mac or you may see this problem recur -- not just with your WD brand drive but with any other external hard drive you might connect to your Mac.

Running the WD uninstaller mentioned above should do this, but if you want to check that it did my post today in Mavericks corrupts external hard drive (on page 43) about the older manual method may help with that.

Were you able to roll back from Mavericks to Mountain Lion. I am trying to do that from the reccovery following the advise from (https://discussions.apple.com/docs/DOC-6161) but when I try to erase disk0 the disk utility gives me a error saying that - "disk utility secure disk erase - can't unmount disk".

Any pointers?

Also, there is no such thing as the WD uninstaller software here - http://support.wdc.com/product/download.asp?groupid=124&sid=214&lang=en. Which one did you use?

Thanks!