Windows 7: The Windows Installer Service could not be accessed

Get "The Windows Installer Service could not be accessed" error message whenever run any msi file.

have tried running msiexec /regserver
also checcked service registry settings which appear to be ok (service is actually running)
other thing to note is that msi files don't appear with an icon, is this related?

Other posts about similar issues with xp talk about re-install of windows installer but as win 7 uses installer 5 i guess this is a none starter?!

it was working fine but i've done something to break it, not sure what!

any help appreciated... otherwise i'm going to have to re-install (after only 2 weeks!!!)

By default, windows makes a system restore. Go to system restore, pick a shown date that you think is before the problem began, this should fix your problem. Your personal information will not be touched. You may have to reinstall programs that you installed after the restore point date that you picked.

Ehem... yeah that's the first thing I though of.... BUT...

...then I remembered that after I'd installed all the software I needed and I thought everything was working OK, I removed all but the last restore point to save disk space!!!

I won't do that again!

Do you have a system image, that you can use?

No system image i'm afraid.

I do have another install of same OS on a dual boot if that's any use. (Different software installed but same os, that one is working fine)

Before I began fooling around with another computer, I would, go to services, by typing services in the startup search. In services go to windows installer. Go to recovery tab. Follow instructions for setting up recovery actions for your computer. This one should work. My policy is always try the easiest step first.

Using the other computer is a bit more difficult. But now I am sure we can get you up and going soon. I have to leave for a while. Post any problems or questions. Someone will be here to help. I will check as soon as I return.

The windows service is "Started". (I have been checking that it was started whenever I get the error, it usually is although on the one or 2 occaisions I have seen it stopped.)

I've set recovery options but still get the same error. (Recovery just set to restart service)
Tried a few restarts too with no joy.
To be honest I was assuming no difference, recovery I assume is just about when the service crashes, and that's not what's happening here..

From scm it looks like the service is running fine, I can start/restart etc.. with no errors... it's just that whenever i run any msi it says "The Windows Installer Service could not be accessed"

BTW: Thanks for all your suggestions and help so far...

I read all the information that you have supplied, again. It appears to me that we can solve your problem. It really is not that difficult, but it involves the registry. This area, always makes me concerned. Get back to me after you save the current registry settings:run>regedit>export. Export to some external device.
As a safeguard, also, make a system image.
In the event that Murphy's Law is invoked we can return to our starting point.

OK have...
Exported registry
Made a sys restore point
System image just about to run now (now that I found some space for it...)

Registry hacks are go...

While you were making your back up, I found the necessary register entry that will help you fix your computer.

The only thing that we are doing is reregistering the Window Server. You mentioned in your intital post that you did something similar, but it did not work. If you did it differently from my instructions you may want to try again. I truly believe that this will work. You checked and you said that the registry setting are ok and that the service is actually running. There is really nothing else I can think of.

My original thought was to take the command from your other computer, but that will not help because the command is ok in your problem computer.

My last piece of advice. I do not like fooling around with the registry, but we have 2 backup, so it should be ok.

Go to run, enter regedit
go to HKEY_local_machine\system\currentcontrolset\services\msiserver

On the right click ImagePath and click modify
you should see or enter msiexec.ele file/v, i.

Contiue and confirm that you want to make the chaneg
click ok and exit registry.

Restart your computer in safe mode. This is done during reboot by holding down f8 and by selecting safe mode. click start
then go to run and enter msiexec /regserver

Hit ok hit start and restart computer in the norml way.

Get back to me so I know what happened