MozyServerError6 and VSS Writers

I like Mozy online backup, as you have probably guessed. I liked Mozy so much that I started offering it as a backup solution to clients and it has worked great. There has been the occasional hiccup but just small things that a quick email to support could solve. Recently though I had a larger problem with MozyPro that required me to call their support line to see if I could get the problem fixed. The MozyPro backup kept failing with the error code MozyServerError6. The Mozy knowledge base was not very helpful on that error code with the suggested course of action being to reboot the computer, do another backup and if the problem persists contact support. I had already tried rebooting the computer, tried another backup and the problem was not going away. Emailing support was easy enough and I got a quick answer, except the answer was the same answer that was in the knowledge base that I had already tried. I realized that I was going to have to call the MozyPro support line and talk to a person to get some help this time.

I called the MozyPro support line and discussed the problem with one of the support technicians. The MozyPro client would start the backup and get to roughly 7% encoding and then it would appear to hang without completing the encoding process. It would also never appear to be able to connect to the Mozy servers. The Mozy technician was nice enough and with a little digging it appeared that the problem was with the Volume Shadow Copy service. The MozyPro client apparently uses the Volume Shadow Copy service to backup locked files. The built in Windows XP backup utility uses the same method to create backups of locked files. Running the command vssadmin list writers listed several VSS writers on the system. Before running a MozyPro backup the status would show “State: [1] Stable”. Starting a backup would cause the status to change to “State: [5] Waiting For Completion” for all the VSS writers, the MozyPro backup would fail and the machine would need to be restarted before the VSS writers status would return to stable. Add to this that a backup using the built in Windows XP backup utility would work perfectly. Once it was determined that the problem with most likely with the Volume Shadow Copy service the Mozy support technician suggested that I need to contact Microsoft because the reason the MozyPro backup was failing was a result of a problem with Windows, not the MozyPro client. Not exactly what I wanted to hear.

VSS Writers

I started by looking at the computer and seeing what was recently installed that might have caused the Volume Shadow Copy service to start failing. The computer itself was recently updated to Windows XP Service Pack 3. Removing the Service Pack did not help, so I started looking at other software that updates regularly. Removing the anti-virus software had no effect. This client uses some custom software that is updated regularly, and talking with the staff they mentioned that there was a larger update recently, right around when the MozyPro backups started failing. That software uses Microsoft SQL Server Express, and I noticed an entry in the Add/Remove software and in the VSS writers list that I did not remember installing when the software was initially installed. The Microsoft SQL Server VSS Writer appeared new to the system, but removing it was not possible since that would break the custom software that this client needed to use. MozyPro was working flawlessly until that additional VSS writer was installed, so my question was how could I get MozyPro to use the default VSS writer, which is the MSDEWriter?

Doing many Google searches I finally came across this page “VSS Backup Fails On Servers Running SQL Server 2005“. There were a few differences like the fact that this computer was running Windows XP Professional, but it sounded similar enough that I went digging into the Windows Registry to see if I could the key that was mentioned. Sure enough I found HKEY_LOCAL_MACHINE -> SYSTEM -> CurrentControlSet -> Services -> VSS -> Settings and set the MSDEVersionChecking to 0. I restarted the computer and started a MozyPro backup and waited, encoding went up to 7%, 8%, 9% and the client was able to connect to the Mozy servers and started to send data up to be backed up. After looking for an answer for four days it appeared that I had finally found a way to get the MozyPro backups working again with Microsoft SQL Server Express.

If you are having problems with MozyPro backups failing and your computer is running Microsoft SQL Server Express give this a try it might work. I won’t guarantee it, and I will not be responsible if something bad happens because you had to edit your registry. I still like Mozy online backup, it is still the best system I have found for backing up a computer offsite easily. I have to be honest though and say it would be nice if Mozy support could actually do more than just say contact Microsoft. It is answers like that from support that causes people to look for other providers. If I was just trying MozyPro for the first time and I was having these kinds of problems I would have uninstalled MozyPro, asked for my money back and tried something else.

Update: Wanted to let people know that this is still working. I was reading the Mozy knowledge base some more and I am not sure why I was getting a Mozy Server Error instead of a Snapshot Error, since this problem seems to be more of a snapshot error. Whatever the problem was changing the default VSS writer does appear to have fixed the problem and MozyPro is backing up the locked Microsoft SQL files.

22 Responses to MozyServerError6 and VSS Writers

  1. I am sorry about the experience you had with our technical support team. The technician you talked to should have identified the work-around, just as you have done for your readers. This clearly would have been the better way. We are striving to attain world-class support, and I assure you we will do a better job.

    Your technical analysis of the VSS problem you were having is impeccable.
    • Mozy uses Microsoft’s VSS writer to backup open files.
    • An update to 3rd party software altered the VSS writer defaults to use a different writer
    • Following the defaults, Mozy was unsuccessful in attempting to use this writer
    • Setting HKLM\SYSTEM\CurrentControlSet\Services\VSS\Settings\MSDEVersionChecking to 0 resets the VSS writer choice back to the former default, which Mozy uses properly

    You correctly identified the issue and its resolution. I appreciate your continued support of Mozy.

    Norris Packer
    Mozy Director of Support
    Decho Corp


    & by the way did I say Thank you?!!!!

    I use Mozy Home and the thing was getting stuck on building the shadow volume set. Sat there, for hours! Doing nothing. Put in the registry patch and it WORKS again!!! Yesssss!!

    Mozy should add this one to their FAQ page & knowledge base so one doesn’t need to go through several google pages to find this!

    Much appreciated. Mozy rocks, especially when it works!

    • Glad it worked for you! I know I spent many hours searching for a fix. That is why I wrote the post just in case there were others that had the same problem.

  3. As Snoopy was wont to say, “Drat, Red Baron!” I put in the registry fix. Mozy was happy for several days. Problem fixed, I thought! Narf! Even after rebooting it’s getting stuck where it was before – creating volume shadow copy snapshot set… We just love Microsoft…

    Running the vssadmin I don’t have SQL so that’s not in my listing but I do have a WMI Writer. Otherwise the rest of my listings match your screenshot. Any other ideas?


    • Two thoughts. Double check your registry and see if the change is still there. I recently had it reversed on me because the software that relied on MS SQL upgraded and I had to do the registry fix again. Mozy also recently released a client upgrade. Check and see what version you are running. Perhaps try and older version and then make sure Automatic upgrades are turned off in the configuration.

      Good luck!

  4. Thanks for the follow-up. I did check the registry and the suggested insertion is still there. I looked more closely at the Mozy config options and there was a box checked ‘enable support for backing up open files’ or similar wording. I unchecked that and it works again.

  5. Thanks for the fix! We had the same issue and your fix worked for us.

    I have to agree that this was all very frustrating. I spent a lot of time comparing the different services and Mozy was the only one that met all of our needs.

    When we hit our first bump in the road with them, I used the online chat support a nice fellow there spent hours with me trying this and that. But ultimately I got an email that said Sorry we can’t fix your issue, call Microsoft. Dude! Not cool!!

    I’m happily backed up now and am going to try a test restore to see how that goes. I’m trying to treat this as “all’s well that ends well” but I have to admit I’m a bit tainted now. Too bad that they’re not helping their paying clients better.

    • Ya it is too bad that their support does not help people with this problem. I know I struggled with it for many hours to try and find a way to get Mozy working again. Glad it helped you.

  6. More follow up – Mozy’s working again! Updated the home to the latest version as well as found the following page:

    On my system (Win XP, SP3) the MS Software Shadow Copy Provider wasn’t running and both the COM+ Event System and COM+ System Application were both set to manual, rather than automatic start. I changed those all to automatic and it’s been fine since. Fingers crossed it will stay that way!

  7. I have a problem that looks like it is related to what you describe (although I do not have SQL on the system), but that does not respond to the solution. Basically, Mozy gets stuck encoding and brings the system to its knees – if I do not manually terminate the backup (by killing the process or rebooting), it will grind for days (at least up to 3) with absolutely no progress. At this point, I have not had a successful backup for over 40 days.

    The latest client is installed, all services listed in the Mozy Knowledge Base article on SnapshotError are set the way they should be, and when the backup is initiated things start out just fine – files encode (file names appear, the bar moves) it communicates with the server, etc., but then somewhere between 29-34% percent encoding Mozy stalls. CPU load goes to >80% and everything stops. Using Sysinternals Process Explorer it is clear that the load comes from the System process, but nothing stands out as the culprit. Using the vssadmin list writers command you can see that the VSS writers have gone from Stable [1] to Waiting for completion [5]. Once mozybackup service has been terminated and the CPU load finally drops (shoots to 100% first), then VSS writers return to stable except for WMI writer, which remains in State 5 apparently forever (until I reboot).

    I added the registry key without any affect on the result described above. Despite the fact that I don’t have SQL or any unusual VSS writers, the problem still sounds like it is somehow related. Do you have any ideas or suggestions?

    Thanks for anything you can offer. /rb

  8. Last night I tried unchecking support for backing up open files to no avail, so I guess the problem is not VSS. Any other ideas as to why Mozy would just hang forever?

    • Sorry off the top of my head I don’t. Have you installed anything new lately? Sometimes that causes a problem. I know I have had problems with Mozy upgrading automatically as well and uninstalling and installing an older version of the client has worked. If you are on Twitter try sending tweet to @mozy and see is he can get you some help.

  9. I appreciate your post – I have been bothered by system freezes which seem to be the result of MOZY Home “inspired” VSS failures. This post seems to address my problem BUT I can not find the registry key you reference. When I go to HKEY_LOCAL_MACHINE -> SYSTEM -> CurrentControlSet -> Services -> VSS -> I don’t find a Settings section – only enum and provider. Any suggestion? Thanks

  10. I haven’t tried that. However, in exploring further and googling error messages that I received I may have solved my problem. When I went to services, I found that I was unable to start MS Shadow Service Provider at all. Based on suggestions on another BB, I tried to reregister the VSS dlls and found I was unable to reregister swprv.dll. I found a post at that directed me export then delete the Shadow Copy Provider, then rebuild the COM+ catalog and reinstall it. I did that yesterday and so far it seems to be working.

  11. Thank you very much. I was having the same problem with MozyPro on SBS. I contacted Mozy Support and got the run around for over 2 weeks. (MOZY SUPPORT IS ABSOLUTELY AWFUL) Spent hours trying to reinstall COM and everything else until I found your quick fix!

    • Glad it helped. I love Mozy but if I can avoid their support I will. I find getting in touch with @mozysupport or @mozy on Twitter is a better route sometimes.

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