At some point of time I started getting an error message “Home PC is unresponsive” when trying to configure backup of one of my machines with Windows Home Server. Backups started failing at that point too. I did a lot of research and found several solutions that I will summarize here. None of them worked for me so I had to do more research and find an extension to existing solution.

After examining system logs with event viewer I found following entries:

Backup of volume (System Reserved) to HPSERVER failed: Microsoft.HomeServer.Backup.NTFS.NtfsReaderException: FileRecord 12 has an invalid magic number
at Microsoft.HomeServer.Backup.NTFS.FileRecord..ctor(Byte* pData, Volume volume, Int64 index, Boolean inUse)
at Microsoft.HomeServer.Backup.NTFS.FileRecord..ctor(Byte* pData, Volume volume, Int64 index)
at Microsoft.HomeServer.Backup.NTFS.FileRecordReader.Next()
at Microsoft.HomeServer.Backup.BackupOp.BackupOperation.DoFileRecordPass()
at Microsoft.HomeServer.Backup.BackupOp.BackupOperation.RunWithoutCatch()
at Microsoft.HomeServer.Backup.BackupOp.BackupOperation.Run()

that lead me to believe that there is a file system error on system reserved partitions. See solution one below:

Solution 1: fix file system errors on your disks

You can either run chkdsk /f <disk letter> for all of your disks or right click on a disk, select “Properties”, then select “Tools” and press “Check Now” under the “error-checking” section. Leave the first checkbox on (automatically fix file system errors) and leave the second one off (scan for and attempt recovery of bad sectors). Click “Start” and the errors will get fixed. If you are doing this on a system disk that Windows boots from then you will need to reboot for system to check it.

This method almost worked for me. The problem was that I had several disks with Windows 7. These have “System Reserved” 100MB partitions at the start of the disk that doesn’t have a drive letter assigned. To check these, you need to temporarily assign them drive letters and then check for errors. You can then delete drive letters.

Solution 2: re-install .NET

Download .NET cleanup tool and remove all .NET frameworks from your computer. Reboot. After than download only the latest .NET framework (at this time it is 4.0) and manually install it. Tool can be downloaded here: http://blogs.msdn.com/b/astebner/archive/2006/05/30/611355.aspx

Solution 3: Registry fix suggested by HP

1. Start regedit.exe
2. Navigate to  “LOCAL_MACHINE\System\CurrentControlSet\Control\Class\4D36E967-E325-11CE-BFC1-08002BE10318″
3. Set “UpperFilters” value to “PartMgr”
4. Reboot
5. Configure Backup in WHS

Please note that it seems that few computers have this registry key. If you don’t – this solution is not for you.

Hope this helps. If you run into similar problem and find other solutions please drop me a comment.