The problem? Backups on my Windows 7 machine started failing.
All I got was a popup window saying that the backups had failed, and suggesting I look in the logs for details. And when I looked in the logs, this is what I found:
Windows Backup failed while trying to read from the shadow copy on one of the volumes being backed up. Please check in the event logs for any relevant errors. (0x81000037)Helpful, huh? "One of the volumes being backed up". No hint as to which one, mind.
But, nothing daunted, I remember that Google is my friend, and I try searching for the relevant string.
And I get pages like this one http://support.microsoft.com/kb/973455#workaroundissue12
Which is obviously about the relevant error message, and is completely incomprehensible. Now, OK, I'm not a Windows expert, but I have been using computers "all day every day" for 30 years. But the problem description, and the solution, mean nothing to me. So although there is a glimmer of light in the darkness, I am certainly not enlightened.
Apparently I have got a problem with a "reparse point" in my "library", and if I remove it, the backup will work. The first problem is that I've never heard of a "reparse point". A few minutes with Google suggests they are some kind of file system sorcery that causes files to appear to be in places where they are not, or making additional or network disk drives appearing as folders in the file system. But knowing that doesn't help much because I have not done anything unusual to my "Library" in months. I believe it contains "My Photos" and "My Documents" and such like, so I have no doubt added things to it. But I haven't done anything unusual, and certainly nothing knowingly involving "reparse points". So it is not obvious where the problem is going to be.
The instructions go on to describe how to use the Windows Command Prompt (Remember that? This is Windows 7, mind) to identify the "junction points" (which is a synonym for "reparse point" --- why have one inscrutable jargon term when you can have two) in my system. And I see that there are many --- about a dozen. One of which, apparently, may be a problem, even though none of them have apparently changed in nearly three years. So although Microsoft give me instructions on how to delete one, I still have no idea how to decide which one to delete.
So, back to Google, which finds me many other people expressing similar frustration.
But then buried away on about page 4 of a long discussion of the problem in a Microsoft forum, I notice a couple of mentions of virus checkers. Which reminds me that, a few days ago Microsoft Security Essentials had detected a problem --- could that be it? I had told it to remove the offending file, but...
So I look in my Security Essentials history, and it indeed tells me that it has quarantined a file -- some kind of Java exploit. So I tell it to remove that file, and try the backup again....
And it fails again.
But some kind of virus checker problem seems a much more plausible cause of the problem than unexpected "reparse points" in my "Library". So, at the suggestion of another forum participant, I turn off Security Essentials and try another backup --- which succeeds!
So the problem is definitely with the virus checker causing the backup to fail, and Backup's messages about inability to read a shadow volume are completely wrong.
Trick is, the virus checker history is not showing me any quarantined items.
Oh, but just a minute... I'm asking to see "Quarantined Items" --- but there is also an option to see "All detected items"... And yes, that is showing another problem that has been found --- a different Java exploit, in the Java cache in my son's account. Which has, apparently, been quarantined -- though for some reason this didn't result in it showing up in the "Quarantined Items" list
So I remove this file, and run the backup again without problem.
So, after over two hours of thrashing about, I learn that if Microsoft Security Essentials quarantines a file, it will prevent Microsoft Backup from backing up your computer until it is removed. That may, or may not, be reasonable.
But neither piece of Microsoft software warns you of this interaction, and that certainly isn't reasonable.
