Hi,I'm running Windows 7 Build 7100. I have installed Visual Studio 2010 beta1 and Silverlight 3 SDKs, so the installer was working. I tried to install SQL 2008 server which failed (unfortunately I thought it was because I downloaded Enterprise Edition from MSDN instead of Developer Edition so I did not copy down any error details). I'm not sure if the SQL failed install has anything to do with the issue but now i get Windows Installer errors whenever I try to install anything e.g. Blend 3, SQL, Office.I have checked that the error is not due to the Registry settings (SQMClient / Disable Settings) and also turned off the Customer Experience Improvement Settings - I found that these were the most common issues for people but they have not solved the issue for me.Is anyone else having installer issues with his build and could anyone point me in the direction of a potential solution? I'm starting to loose hair over this one!Johnny

Johnny - If you go into Task Manager, and go to the Processes tab, and click on the Show All Processes from all users button, do you see anything that remotely looks like an installer, MSI or otherwise? Also, on the Services tab, check to make sure the Trusted Installer service is stopped before you try installing anything.

Wolfie - you're a champion! There was a sneaky installer running under all users processes. Now i've just got to find a use for the clumps off hair i pulled out....

Johnny - No worries - sometimes it takes a fresh pair of eyes to look at a problem in a different light.

Awesome, thanks! I have the Beta of Visual Studio Ultimate 10 installed, and needed to uninstall it to install the newly released version. I had already checked the processes tab for any instances of MSI or similar, but had not looked under 'All Users'. Found it, killed it, and the uninstall proceeded without further hic-up.

Thanks mate - solved it for me tooWill