What can I do about Windows 7 Backup error 0x81000037, apparently caused by reparse points?

What Microsoft says

If you read the MSKB article you linked more closely, you will see that error 0x81000037 apparently

"occurs if the reparse point is a mounted volume that contains compressed files (for example, multimedia files, .zip files, and so on)"

(emphasis mine)

In the section Workaround of the same document, they emphasize that you should

confirm the folder Type is Mounted Volume.

At the end they say

By design, Windows Backup does not traverse reparse points on a computer. However, if a reparse point is directly added to a Windows 7 Library, or if any of the child nodes of a reparse point is directly added to a Windows 7 Library, Windows Backup traverses these locations. This could cause several issues during the backup process.

My analysis

Reformulating what Microsoft says, out of all the reparse points you have only the ones which are "mounted volumes" are a problem (and then only if they contain "compressed files" and are included in a Win7 Library).

Looking at your list of reparse points, none of them seem to be mounted volumes (rather normal junctions and symlinks; see below for details), so I dare guess that your reparse points are not the real source to your problem!!

In my case I got the same error message 0x81000037 but it was actually caused by Sophos Anti-Virus refusing access to a file in the Shadow Copy. Putting an exception for that file (a harmless autorun.inf which I checked by hand) into the Antivirus configuration solved the problem without removing any junctions (like you, I didn't have mounted volumes).

My answer

Apart from removing actual mounted volumes (see below), make sure nothing else interferes with reading the Shadow Copy. Using the Process Monitor as suggested by Duncan sounds like a good idea for that.

Don't remove innocent junctions, that won't help. In fact, you can replace Mounted Volumes by Junctions to make Windows Backup work :-).

More Details about Mounted Volumes

Using Hard Link Shell Extension you can create "Mounted Volume" links, e.g. of your CD drive, and "Junctions". This is the HardLinkShellExt context menu I get when dragging my CD drive into a folder with the right mouse button:

For tests I created both a junction and a mounted volume. See what it looks like using DIR /AL, Windows Explorer and the folders' "Properties" tabs:

Comparing to Microsoft's screenshot from the above KB article, we learn that DIR calls both junctions and mounted volumes <JUNCTION>; Windows Explorer differentiates them by using a folder or drive icon, but to be sure you can open the properties tab. Looking back to the output if DIR, the mounted volume is a reference starting with \??\Volume, which you don't have in your question; that is why I don't think that MSKB article applies to you.

Replacing Mounted Volumes by Junctions

For people who do use Mounted Volumes and include them in a library (unlike to OP), consider replacing them with junctions; I did a test and this solved the problem:

• with mounted volume

• with junction