It all started with the Backup utility in Windows XP Professional. (It's also available with the Home edition, please see the bottom)

Some time ago, when I tried to backup some files using the Backup utility, the process failed and gave no specific warnings, and the log mentioned that there was something wrong with Volume Shadow Copy Service (VSS), when VSS was not used, the backup process proceeded smoothly. The error message in the Backup log follows:

Error returned while creating the volume shadow copy:80042301

According to the Services MMC snap-in (run services.msc), the VSS was up and running, however, the Event Viewer MMC snap-in (run eventvwr.msc) showed that the VSS did encountered problems, with Event ID 8193, 5013 and 12291. Also, running "vssadmin list writers" and "vssadmin list shadows" resulted in errors. The error messages in the log follows:

Error ID: 8193

Event Type:     Error
Event Source:   VSS
Event Category: None
Event ID:       8193
Date:           2004-07-27
Time:           5:49:27 PM
User:           N/A
Computer:       (deleted)
Description:


Volume Shadow Copy Service error: Unexpected error 
calling routine IEventSystem::Query. hr = 0x80040155.
For more information, see Help and Support Center at
http://go.microsoft.com/fwlink/events.asp.

Data:
0000: 57 52 54 57 52 54 49 43   WRTWRTIC
0008: 32 31 33 37 00 00 00 00   2137....
0010: 57 52 54 57 52 54 49 43   WRTWRTIC
0018: 32 30 37 38 00 00 00 00   2078....

Error ID: 5013

Event Type:     Error
Event Source:   VSS
Event Category: None
Event ID:       5013
Date:           2004-07-27
Time:           5:49:27 PM
User:           N/A
Computer:       (deleted)
Description:

Volume Shadow Copy Service error: Shadow Copy writer 
Microsoft Writer (Bootable State) called routine 
CVssWriterShim::Subscribe which failed with status 
0x8000ffff (converted to 0x800423f4). For more 
information, see Help and Support Center at 
http://go.microsoft.com/fwlink/events.asp.

Data:
0000: 57 53 48 43 4f 4d 4e 43   WSHCOMNC
0008: 32 32 33 30 00 00 00 00   2230....
0010: 57 53 48 57 53 48 4d 43   WSHWSHMC
0018: 33 31 31 35 00 00 00 00   3115....

Error ID: 12291

Event Type:     Error
Event Source:   VSS
Event Category: None
Event ID:       12291
Date:           2004-07-27
Time:           5:49:31 PM
User:           N/A
Computer:       (deleted)
Description:

Volume Shadow Copy Service error: Error on 
creating/using the COM+ Writers publisher interface: 
IVssWriter::RequestWriterInfo, GatherWriterMetadata 
[0x8000ffff]. For more information, see Help and 
Support Center at http://go.microsoft.com/fwlink/events.asp.

Data:
0000: 42 55 45 43 58 4d 4c 43   BUECXMLC
0008: 33 35 36 34 00 00 00 00   3564....
0010: 42 55 45 43 58 4d 4c 43   BUECXMLC
0018: 33 35 36 32 00 00 00 00   3562....

After Googling around, there didn't seem to be any solution without re-installing Windows, until "0x80040155" was used (from Event ID 8193) for Googling, several relevant results turned up.

The first result was this, which pointed the culprit to the COM+ component. So I tried to start COM+ System Application via the Services MMC snap-in, and it indeed failed. That webpage also pointed to here at JSI FAQ and here at Microsoft detailing how to repair a damaged COM+ catalog.

The second result was this, it was a much simpler solution, simply run "regsvr32 ole32.dll". After running the command, COM+ System Application could finally be started, after that, I restarted VSS (stopped it and started again), and voila! Now it's okay, "vssadmin list writers/shadows" stopped giving errors, and the Backup utility could also be used with VSS.

So there's it, if the VSS is failing, give (any or both) the above solutions a try before re-installing Windows. Happy computing to all!

**** Update on 2006-08-26 ***

There's a very comprehensive post about fixing VSS issues at 2BrightSparks' forum, recommended.

Notes:

• The Backup utility of the Home edition is not installed by default. To install it, navigate to the "\Valueadd\msft\ntbackup" folder on the XP Home CD, and run (double-click) the "ntbackup.msi" file.
• One of the functions of VSS is to make backing up files that are opened and being used possible. Without VSS, those files, such as Outlook's .PST files when Outlook is being used, and some system files, will not be backed up. For more information about VSS, please refer to this Microsoft webpage.