The problem started with trying to install Framework 4 updates from WSUS (to a specific machine). They fail with error: "The Windows Installer Service could not be accessed." (0x80070641) From what I can tell that EXE update is trying to launch VSSetup (? - C:\Windows\Installer\32266b4.msi) and that MSI fails to execute. The Windows Installer service starts fine on it's own then stops right when the error pops up. EventID: 1013: "Internal MSI error. Installer terminated prematurely." That lead me to run SFC. SFC told me msi.dll was no good. However it also tells me the source is no good either. At any rate I booted into recovery mode from a flash drive and blew out the msi.dll file. Went back into windows and it replaced the file but again tells me the file is no good. From here I restored from a backup. Still no good. Restored from my oldest back of 23 days ago and it's still no good! Out of despiration I went back into recovery mode and replace BOTH system32 and WINSXS with a known good file. SFC still tells me the hash doesn't match and "Could not reproject corrupted file" Any idea what's going on here? At this point I can not install any MSI packages. Am I chasing a ghost and in fact something else is wrong? 2011-09-27 11:50:39, Info CSI 000000ce [SR] Verify complete 2011-09-27 11:50:40, Info CSI 000000cf [SR] Verifying 100 (0x0000000000000064) components 2011-09-27 11:50:40, Info CSI 000000d0 [SR] Beginning Verify and Repair transaction 2011-09-27 11:50:48, Info CSI 000000d1 [SR] Cannot repair member file [l:14{7}]"msi.dll" of Microsoft-Windows-Installer-Engine, Version = 6.1.7601.17514, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, file is missing 2011-09-27 11:50:49, Info CSI 000000d2 Ignoring duplicate ownership for directory [l:108{54}]"\??\C:\Program Files\Common Files\microsoft shared\vgx" in component Microsoft-Windows-IE-VGX, Version = 9.4.8112.16421, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral 2011-09-27 11:50:49, Info CSI 000000d3 [SR] Cannot repair member file [l:14{7}]"msi.dll" of Microsoft-Windows-Installer-Engine, Version = 6.1.7601.17514, pA = PROCESSOR_ARCHITECTURE_AMD64 (9), Culture neutral, VersionScope = 1 nonSxS, PublicKeyToken = {l:8 b:31bf3856ad364e35}, Type neutral, TypeName neutral, PublicKey neutral in the store, file is missing 2011-09-27 11:50:49, Info CSI 000000d4 [SR] This component was referenced by [l:202{101}]"Microsoft-Windows-Foundation-Package~31bf3856ad364e35~amd64~~6.1.7601.17514.WindowsFoundationDelivery" 2011-09-27 11:50:50, Info CSI 000000d5 Hashes for file member \??\C:\Windows\System32\msi.dll do not match actual file [l:14{7}]"msi.dll" : Found: {l:32 b:vs8J5wslsDeJPYj4rxockFhHpIwA9CnhlOF7jkXz+j0=} Expected: {l:32 b:TmPMyBRhGDhj3kZ8eUUuWlIU3RQuQHfDn1QtVb0jjFk=} 2011-09-27 11:50:50, Info CSI 000000d6 [SR] Could not reproject corrupted file [ml:520{260},l:46{23}]"\??\C:\Windows\System32"\[l:14{7}]"msi.dll"; source file in store is also corrupted Any ideas would be greatly appreciated!

1. I recommend to move this problem into WSUS forum http://social.technet.microsoft.com/Forums/en-US/winserverwsus/threads 2. Before any consistency check, I would recommend look into WindowsUpdate.log (http://support.microsoft.com/kb/902093/en-us) and ReportingEvents.log , as well as into application eventlogs. 3. Is this problem of one workstation/server or more computers? 4. You should have current version of installer

Thanks for the reply but this has nothing to do with WSUS. I was simply explaining how I stumbled across the issue. Since then I have been installing the update manually. I've given all log information including the MSI log. Yes, only one machine. My apologies if I did not get that across in my original post. I should also note that I skipped a step in my troubleshooting. Before I blew out the MSI file I also ran SFC in recovery mode and did an offline check. That check also failed with the same reasons as the online check. After extensive searching I came up empty. My last nail to whack before reloading the OS from scratch was to do an in-place install/upgrade of the OS. Yuck! That took the machine back to a raw R2 SP1 state and it fixed the issue. Hopefully the updates will re-install without further issue. On a side note, when the machine came back up for the first time a message popped up that said there was a problem with framework 4 and not to reboot until the issue had been fixed (gee, go figure!). No clue what it did but it took a long time to run. After the reboot everything seemed to be golden.