New article published in Microsoft Support. It should be available soon. In the meantime, here’s what I’ve put together. Hope it helps some people out there!

Symptoms

Error when performing online P2V. Stops at 40 percent every time.

Job result in SCVMM Admin Console
Error (13243)
The snapshot creation failed because the VSS writer {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f} on source machine xxx did not respond within the expected time interval.
(Internal error code: 0x809933BB)

Recommended action:
Ensure that VSS writer is functioning properly and then try the operation again.
4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f is the Shadow Copy Optimization Writer

Event in Application Event Log on Source machine
Log Name:      Application
Source:        VSS
Date:          2/15/2010 6:19:11 PM
Event ID:      8193
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      ServerName.Domain.com
Description:
Volume Shadow Copy Service error: Unexpected error calling routine ConvertStringSidToSid.  hr = 0x80070539.

Operation:
   OnIdentify event
   Gathering Writer Data

Context:
   Execution Context: Shadow Copy Optimization Writer
   Writer Class Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f}
   Writer Name: Shadow Copy Optimization Writer
   Writer Instance ID: {d19e5030-d027-4b0d-b783-02d87be808f4}

Cause

Volume Shadow Service (VSS) 'Shadow Copy Optimization Writer' is not fuctioning correctly. In the event log above the issue involves resolving a SID.

Resolution

  • There were unresolvable SIDs in the 'Administrators' group on the SCVMM Source machine. These were deleted.
  • Followed steps in 'KB947242 - A temporary profile is loaded after you log on to a Windows Vista-based system' to resolve issue where customer's profile was deleted from the system (in this case the profile was simply corrupt).
  1.  
    1. Open regedit and locate 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\ProfileList'
    2. Under the ProfileList subkey, delete any subkey that is named SID.bak.

Note SID is a placeholder for the security identifier (SID) of the user account that is experiencing the problem. The SID.bak subkey should contain a ProfileImagePath registry entry that points to the original profile folder of the user account that is experiencing the problem.

More Information

Shadow Copy Optimization Writer
Beginning with Windows Vista and Windows Server 2008, this writer deletes certain files from volume shadow copies. This is done to minimize the impact of Copy-on-Write I/O during regular I/O on these files on the shadow-copied volume. The files that are deleted are typically temporary files or files that do not contain user or system state.

The writer name string for this writer is "Shadow Copy Optimization Writer".

The writer ID for the shadow copy optimization writer is 4DC3BDD4-AB48-4D07-ADB0-3BEE2926FD7F.

In-Box VSS Writers
http://msdn.microsoft.com/en-us/library/bb968827(VS.85).aspx