Windows Installer Inaccessible

[jtaylor914]

Starting yesterday, I've encountered a major problem with my year-old computer. Whenever I try to install or uninstall a program or even a Windows Update, I get the error:

“The Windows Installer Service could not be accessed. This can occur if the Windows Installer is not correctly installed. Contact your support personnel for assistance.”

I am running Windows 7 Professional 64-bit Service Pack 1. I have tried the following solutions, to no avail:

1) Go to services.msc and start Windows Installer.

When I try that, I get the error:

“Windows could not start the Windows Installer Service on Local computer. Error 5: Access is denied.”

2) Un-register and re-register the Windows Installer using Command Prompt.

This had no effect at all when tried.

3) Run sfc/scannow from Command Prompt.

I tried that and it said there were no integrity violations.

4) Install the latest Windows Installer version.

I already have the latest version.

5) Run regedit.exe. Navigate to HKEY_LOCAL_MACHINE/SYSTEM/CurrentControlSet/services/msiserver then right click on WOW64 and select “Modify.”

I do not have "WOW64" in msiserver

6) Delete C:\Windows\system32\msiexec.exe and restart.

I recieve a message telling me I need permission from myself to access the file in order to move/rename/delete it.

7) Re-install Windows Installer Service by downloading MSIServer

I merged the file, but it had no effect.


So here I stand: stumped. This is clearly a common problem, but no one else's solution has worked yet. Please, throw all of your ideas at me. Thanks.

 

[danny2000]

Try going back a few days with Windows System Restore; That should fix that.

 

[jtaylor914]

Try going back a few days with Windows System Restore; That should fix that.

System Restore can't find any saved restore points... which is odd, considering it creates a restore point every time a new program is installed. Also, attempting to create a new restore point brings up the error message:

"The restore point could not be created for the following reason:

Insufficient storage available to create either the shadow copy storage file or other shadow copy data. (0x8004231F)

Please try again."

which is also odd, as I have over 100GB free on C: and 2TB free elsewhere.



Update: I was able to give myself permission to remove the msiexec.exe files from their directories (system32 and sysWow64) and then run sfc/scannow, which then found a number of corrupt files related to the installer and replaced them from its "store." This produced no change, however.

 

[jtaylor914]

I have solved the problem unexpectedly. I suspected malware and was going to run a scan on my computer from my laptop, and so went to remove all security settings from my C: drive. The instant I applied "Full Control" Audit settings to the user group "Everyone," Windows Update was able to complete an install and Windows Installer began functioning normally again.

I don't know what to think about this, as I still don't know what caused the problem in the fist place, but this is a solution

 

[danny2000]

If you suspect malware/viruses, it is best to reinstall everything, as one can never be certain that every is hunky dory.

 

[supasieu]

Scan for rootkit with Kaspersky Rescue Disk, and run some anti-virus, malware/adware removal apps.
Try this tweak and run repairs on your corrupted PC
http://www.tweaking.com/content/page/windows_repair_all_in_one.html

Hope it helps,