Error “The Windows Installer Service could not be accessed” in Windows 7/Vista

When you try to install a program which uses Windows Installer in a Windows 7/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.


Start the Windows Installer service

  1. Click Start, type Services.msc and press {ENTER}
  2. Double-click Windows Installer
  3. Set the Startup type of Windows Installer to Manual
  4. Click Start to start the service. Note down the error message if any.
  5. 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:

  1. Download (for Windows Vista) | (for Windows 7).
  2. Unzip the file and extract msiserver.reg to the Desktop.
  3. Right-click msiserver.reg and choose Merge.
  4. Click Yes when asked for confirmation.
  5. Restart Windows.

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About the author

Ramesh Srinivasan founded back in 2005. He is passionate about Microsoft technologies and he has been a Microsoft Most Valuable Professional (MVP) for 10 consecutive years from 2003 to 2012.

48 thoughts on “Error “The Windows Installer Service could not be accessed” in Windows 7/Vista”

  1. 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)

  2. 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!!!!

  3. THANK YOU!!!! I’ve been having a problem for months and bought a program to fix this today but of course it didn’t help. Yours was the correct solution and soooo simple. Thanks.

  4. I tried both solutions and I am still getting the same error messeage. I haven’t had any problems with anything other than updating and installing the newest version of iTunes.. Do you have any other suggestions?

  5. Help! My Windows Installer is not listed and your second solution should be the fix. However, when I get to the “Merge” step, clicking on “Merge” just opens Notepad with the details of the registry fix. No request for confirmation or anything that suggests the fix is working. What am I doing wrong?

  6. Fixed it!!!! Had the default program set to “Notepad” for the .reg file extension. Opened it with regedit and it installed Windows Installer. Have been able to install all the outstanding Windows Updates. Looking good!

  7. yes ok thanks i worked it out my self but thank you for that but it still did not work but than i found a little you tube video and all i had to do i go into services and turn on the windows installer

  8. Thank you, thank you, thank you and bless you 🙂

    You have saved my sanity. I have been trying to solve this problem for a full 48 hours and have had very little sleep in that time.

    Both of your solutions worked together for me.

    I started with solution 2 (Windows Installer Registry Fix) as Windows Installer was missing in the Services. After downloading and unzipping, it opened in Notepad when I clicked Merge so I had to “Import” it into “regedit” instead. I then restarted windows Vista.

    I then proceeded with solution 2 as outlined and there were no error messages. Yay! 🙂

    Then I installed a program successfully without a single error.

    Many thanks again. I can now go and get some much needed sleep.
    Sweet dreams 🙂

  9. Thanks! A fix that actually worked. I have been trying to chase down a solution to a disfunctional VISTA update problem. Lots and lots of tries and midifications, none worked til the msiserver.reg download.

  10. I have tried to replace misiserver.reg have now got it in Services but when open int says (Configuration manager,The specified device instance handle does not correspond to a present device)
    John F

  11. No fix so far has worked for me. Including this. Tried CCleaner, msisever.reg, updating directly from microsoft website – Nothing! Please help.

  12. Cheers, been trying for a couple of days now, quite a easy fix (once you do it properly). Import saved file into service (in regedit) and restart. Couldn’t be simpler. Thanks.

  13. Many thanks Ramesh, your msiserver registry key fixed the problem on my Windows Vista 32-bit operating system. I can now install / uninstall programs using Windows Installer again and Windows Update has also cleared a recent backlog of failed installs. Well done for sharing such a neat solution!

  14. Hallelujah! I’ve been working on this for days, searching online for help! Same troubles others here had. Not able to install any updates. Windows Installer missing in Services. Thanks to WinHelpOnline plus Melanie’s & Holly’s notes to help when the Merge didn’t work. Followed instructions, restarted, and then tried the Windows Updates again. Voila, they finally worked. What a relief.

    Thank goodness for this site.

  15. There’s an error at the services.msc thing. When i Click start it says “Error 1058: The Service cannot be started, either because it is disabled or because it has no enabled devices associated with it” please help me fix the error thanks

  16. Thank you!! Issue resolved by following Windows Installer Registry Fix and helpful directions from Melanie and Holly in comments.

  17. Thank you so much, I’ve been trying to fix this for ages. I had to do a manual import as msiserver.reg opened in Notepad. So, right mouse on the file, Open With > regedit.reg (C:/Windows/regedit.exe) Then don’t forget to reboot, it won’t work until you do.

    Thanks again.

  18. I wish I could fix this problem for me. I was wondering if I could uninstall service pack 2. and then re install it.

  19. Same problem as Cappy. I tried ti install the new itunes with no luck. I get an error mssg. Someone told me to uninstall then reinstali itunes. When I tried to uninstall I got the mssg “windows installer could not be accessed. Tried a few so called solutions nothing is working for now.

  20. Windows installer was comletely missing from my services list (ie. cmd/services). I couldn’t re-install Vista because it came pre-installed with my laptop 5 years ago, no disc. Searched forums for solutions, only one worked: (the windows registry installer fix).

    BUT, I had to manually import the file (ie. right click -> open with -> regedit.reg, browse and find it at C:/Windows/regedit.exe), and then restart your machine. THANK YOU KATIE for explaining how to do this, as merging didn’t work for me. Now, I am back up and running! Thank you, thank you, thank you!!!

  21. If you’re running Vista (mine is 32-bit) and you see the window pop up as shown above, you’ll need to do a manual import as Katie has advised. I couldn’t download and install anything, but thanks to Katie’s advice, I’ve been able to download all my updates – especially the update for Adobe! Thanks, Katie!!

  22. i have had same problem but got error 216 0xd8 when i did the Manuel thing then start for first one that happend but on second one it said it did everything right i restarted computer and windows installer still didnt work

  23. Mine is already set to manual, and merging the new file didn’t do anything. it was the same one already installed, I just had to activate it.

  24. it said “The Windows Installer service on local computer started and then stopped.Some services stop automatically if they are not in use by other services and programs.”

  25. Ramesh,

    Look up AWESOME in the dictionary, and your picture is there. You provided the fix for a problem that has plagued me for so long. Thank you so very, very much!


  26. I cannot tell you how MANY websites, solutions, options I have tried, and then I stumbled upon this. You are a god among mere mortals, thank you thank you thank you!! I worked perfectly!

  27. RT quote:I cannot tell you how MANY websites, solutions, options I have tried, and then I stumbled upon this. You are a god among mere mortals, thank you thank you thank you!! I worked perfectly!
    many tq

  28. Thnx you very much it was working well.
    i was always search many solution but, they was giving a wrong ida.
    But it was a simple way.


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