Windows update error 0x8024402F

I run yesterday into a weird error, for which I spent half of day to solve the problem. It’s unlikely you’d run into the same problem, so this is more for me to remember what I did to fix it in case I run into this again…

Yesterday I upgraded my laptop to Windows 8 Pro and installed Office 2013 Consumer Preview (upgrade from Win7 Ultimate/Office 2010). After the upgrade, when I tried to install latest Windows updates, I kept getting error 0x8024402F.

I tried the Help page on the error code, I launched the troubleshooter there (which claimed it could be a problem with the server connection, and claimed to have applied fixes), but all lead to nothing.

Knowing in the past I had trouble with Windows Update I searched my blog, which pointed out to problems related to UseWUServer set when I joined CorpNet. I left corp.microsoft.com domain and joined my home domain, but that only cost me 2 reboots and still didn’t fix anything.

I searched the the net for the error code, I found more KnowledgeBase pages with more FixIt installers which also did not fix the problem.

From http://support.microsoft.com/kb/836941 I found out the error code means WU_E_PT_ECP_SUCCEEDED_WITH_ERRORS. Further searches on the named error pointed to a WindowsUpdate.log file (instructions for reading it are at http://support.microsoft.com/kb/902093).

I looked in the log file and it contained more error details like this:

1060 15a8 PT WARNING: ECP: Failed to validate cab file digest downloaded from http://www.download.windowsupdate.com/msdownload/update/software/svpk/2008/06/1319061_d1590aa04b224974f0cf46ee7937bda90a815268.cab with error 0x80246003

Great, now I was looking for a different error code, 0x80246003. A search on the error number on Internet didn’t find any solution. The only thing I could find is a KB page http://support.microsoft.com/kb/938205 where I learned the error code 0x80246003 is WU_E_DM_UNKNOWNALGORITHM “A download manager operation could not be completed because the file metadata requested an unrecognized hash algorithm.”
Further searches on the named error lead nowhere. I tried re-registering the cryptographic providers dlls, comparing with other machines where things were working, all to no avail.

I run ProcMon searching for failures (when in doubt, run Process Monitor), but again this didn’t help.

I searched the internal Corpnet site for the error code or named error, but that also didn’t lead to a solutions.

Ultimately, I searched the source code. The error code is returned from only one place, from a failed test checking whether test keys are allowed. This had 2 parts:

- checking whether I had a file AUTest.cab in %windir%\SoftwareDistribution folder

- checking whether HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\Test\AllowSHA1ContentHash = (dword)1

ProcMon should have shown these as well (at least the first one, to begin with), probably I just missed the line between so many other failures.  Anyway, I set easily the registry value, but I didn’t have the file on any other machine where things were working fine.

After more CorpNet searches I found on http://mswikis/wukipedia/Wiki%20Pages/What%20is%20autest.cab.aspx where to get this test cab file (I needed to obtain a latest version anyway, since the file is signed and expires every 2 weeks).

I copied it to SoftwareDistribution folder, stopped and restarted the Windows Update service (‘net stop wuauserv’/’net start wuauserv’), and next time I tried Windows Update the update finally succeeded! After that I deleted the test cab file, and after that the updates still seem to work fine.

I suspect some internal test qfe was installed on my laptop when I joined CorpNet a while ago (giving the old ‘svpk/2008/06’ date of the update, suggesting some Win7 pre-service pack timeframe), and it was causing trouble now.

Anyway, I’m glad the problem seems fixed, but just in case here is this article to remind me the solution in case I run into this ever again.