Here's a quick heads up on a call we've been getting a lot over the past couple days.  Hopefully this will save you some time and a phone call if you run into it:

Problem Description: You may experience an issue where your clients report in and detect updates but the updates won't install.  You may also see something like the following in your windowsupdate.log:

2008-01-24 16:05:47:877 1332 588 DnldMgr ** START ** DnldMgr: Downloading updates [CallerId = AutomaticUpdates]
2008-01-24 16:05:47:877 1332 588 DnldMgr *********
2008-01-24 16:05:47:877 1332 588 DnldMgr * Call ID = {88BAF78F-7557-430F-B6F6-9313471F0915}
2008-01-24 16:05:47:877 1332 588 DnldMgr * Priority = 2, Interactive = 0, Owner is system = 1, Explicit proxy = 0, Proxy session id = -1, ServiceId =
{3DA21691-E39D-4DA6-8A4B-B43877BCB1B7}
2008-01-24 16:05:47:877 1332 588 DnldMgr * Updates to download = 1
2008-01-24 16:05:47:877 1332 588 Agent * Title = Update for Windows XP (KB916846)
2008-01-24 16:05:47:877 1332 588 Agent * UpdateId = {19F54F87-0EBB-4CB6-9F52-8300B52AF6B1}.101
2008-01-24 16:05:47:877 1332 588 Agent * Bundles 1 updates:
2008-01-24 16:05:47:877 1332 588 Agent * {E4D32654-0323-4219-BB6B-773D4CFCFD57}.101
2008-01-24 16:05:47:877 1332 588 PT +++++++++++ PT: Synchronizing file locations +++++++++++
2008-01-24 16:05:47:877 1332 588 PT + ServiceId = {3DA21691-E39D-4DA6-8A4B-B43877BCB1B7}, Server URL =
http://svr/ClientWebService/client.asmx
2008-01-24 16:05:47:955 1332 588 DnldMgr *********** DnldMgr: New download job [UpdateId = {E4D32654-0323-4219-BB6B-773D4CFCFD57}.101] ***********
2008-01-24 16:05:47:955 1332 588 DnldMgr * Queueing update for download handler request generation.
2008-01-24 16:05:47:955 1332 588 DnldMgr Generating download request for update {E4D32654-0323-4219-BB6B-773D4CFCFD57}.101
2008-01-24 16:05:48:142 1332 588 Handler Windows Patch download for UpdateId = {E4D32654-0323-4219-BB6B-773D4CFCFD57}: selected action is download full-file.
2008-01-24 16:05:48:158 1332 588 DnldMgr *********** DnldMgr: New download job [UpdateId = {E4D32654-0323-4219-BB6B-773D4CFCFD57}.101] ***********
2008-01-24 16:05:48:455 1332 588 DnldMgr * BITS job initialized, JobId = {859CFE63-832D-4BC6-B7DB-7662A6FFE8DC}
2008-01-24 16:05:48:736 1332 588 DnldMgr * Downloading from http://svr/Content/7E/42D6770F6A7BE35119D194CFCD77D93948BFD67E.exe to
C:\WINDOWS\SoftwareDistribution\Download\341405760511da541d4a29edd350a830\WindowsXP-KB916846-x86-ENU.exe (full file).
2008-01-24 16:05:48:877 1332 e3c DnldMgr WARNING: BITS job {D58ECA81-71E2-45D2-B200-80F0B871877F} failed, updateId = {6D6FD00B-5750-4C4B-B6B2-4D7D0C078F2E}.100, hr = 0x80190194, BG_ERROR_CONTEXT = 5
2008-01-24 16:05:48:892 1332 e3c DnldMgr Progress failure bytes total = 3987762, bytes transferred = 0
2008-01-24 16:05:48:892 1332 e3c DnldMgr Failed job file: URL = http://svr/Content/0A/32A2DF3D4C54273164C8D0F5A4B645890BC0580A.CAB, local path =
C:\WINDOWS\SoftwareDistribution\Download\48004cc97fa5f73d2c849bfafb78f796\OLKINTL.CAB
2008-01-24 16:05:48:971 1332 e3c DnldMgr Error 0x80244019 occurred while downloading update; notifying dependent calls.
2008-01-24 16:05:49:002 1332 588 Agent *********
2008-01-24 16:05:49:002 1332 588 Agent ** END ** Agent: Downloading updates [CallerId = AutomaticUpdates]
2008-01-24 16:05:49:002 1332 588 Agent *************

(Note that I added the bold red color above for emphasis, yours won't look that way)

Cause: This can happen if the default website properties are replaced by the virtual directory from Symantec Endpoint Protection Manager.

Resolution: To resolve this you will need to reinstall WSUS on port 8530 if you still want to keep both products on the same machine.  If doing that, don’t forget to update the GPO or script you configured to point the clients to WSUS.

Here are some notes from Symantec about it:

http://service1.symantec.com/SUPPORT/ent-security.nsf/docid/2007110813315548

I hope you don't run into this but if you do maybe this will save you some time and heartache.  And special thanks to Support Engineers Joao Madureira and Steve Thomas for getting this documented here.

J.C. Hornbeck | Manageability Knowledge Engineer