When you try to install a program which uses Windows Installer in a Windows Vista computer, you may receive the following 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.

This error may occur even though Windows is already in normal mode.
Resolution
Start the Windows Installer service
- Click Start, type Services.msc and press {ENTER}
- Double-click Windows Installer
- Set the Startup type of Windows Installer to Manual
- Click Start to start the service. Note down the error message if any.
- Click OK.
Windows Installer Registry Fix
If the above steps do not help or if the Windows Installer service is not listed in the Services applet, follow these steps:
- Download msiserver.zip and save it to Desktop.
- Unzip the file and extract msiserver.reg to the Desktop.
- Right-click msiserver.reg and choose Merge.
- Click Yes when asked for confirmation.
- Restart Windows.
Related Posts
- Miscellaneous Registry Fixes for Windows 7/XP/Vista
- Fix for Error “Windows Resource Protection Could Not Start the Repair Service” When Running SFC in Windows 7 and Vista
- Fix: Change Analysis Diagnostic Does Not Install in Windows XP SP3
- How to Install and Run the Windows Installer Cleanup Utility if Windows Installer Fails to Work
- Determine the Target Path of Windows Installer Shortcuts
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This did not help in our situation, however when trying to get into Safe Mode on the Windows 7 64-bit computer we were promted with a repair utility. Upon executing that repair utility, and opting not to restore to previous point the problem is gone. This utility ran for about an hour.
You can simply get to this utility on Wondows 7 by forcing the computer to shut down while booting Windows. On the next reboot of the computer, you should be promoted with this utility or to start Windows normally.
I tried both methods, but still doesn’t work for me
many thanks for your solution which worked straight away, when various solutions offered by MS’ own help/support sites got me nowhere (albeit it was on one of their sites that i found the link to your site).
Many thanks, I from Russia write on russia. There was a problem with updating of system and fitter Windows. Three days could not correct. Has casually found your site. Has made as at you all is written also it has turned out. Thanks once again.
Thank you so much so far no other advice /support even form microsoft had worked until I came across this. Am so grateful.
Thanks
First solution doesn’t help me: the Windows Installer service is already running.
Second method doesn’t help me either: I’m not brave enough to download and merge random (and undocumented) registry entries from the internet.
OOOOMMMGGG!!! THANKYOU SOOOO MUCH!!!! IT WORKED!!! I did what the microsift website said and none of them worked! They had like 5 different things to try. I’ve been working on this forever. Found this article and it took me like one minute to fix it!!! Thankyou!!!!
many thanks for your solution which worked straight away, when various solutions offered by MS’ own help/support sites got me nowhere (albeit it was on one of their sites that i found the link to your site)
thank you this info really works!
God bless you! :)
i tried the above instruction and it didn’t work.I need to know how to delete this ICON it left on my desktop. That doesn’t do anything. My PC was already set @ manual and no matter how many times I click START I received another message “SERVICE WILL STOP AUTOMATICALLY IF NOT IN USE”.
I also, noticed that the line between ‘MANUAL’ & START read ‘SERVICE STATUS’ stopped. I need to know how to change this. This has to be the problem.
How do I change that status. The Three other keys are greyed out at this point.
If anyone out there actually knows or understand this please help me.