You may encounter the following error message during an installation of SQL Monitor.  The error occurs during the running of MSI for the Base Monitor portion of the installation.

The error appears to be caused by one or more of the following:

• The installer exe is marked as "Blocked"
• The previous service that is uninstalled during the update is installed is only marked as "to be deleted"; it still shows up as Disabled in the Services console
• Some files in the working directory for SQL Monitor are conflicting with new files being installed

To be able to install successfully, follow these steps:

1. Uninstall any SQL Monitor components ( Start -> Run -> appwiz.cpl )
2. Check if SQL Monitor Base Monitor service is still in the services console ( Start -> Run -> Services.msc ) and if so, then restart the machine you are installing on
3. Ensure that there are not files left in %ProgramFiles%\Red Gate\SQL Monitor and/or that the SQL Monitor folder there does not exist.
4. Rename the %ProgramData%\Red Gate\SQL Monitor folder to %ProgramData%\Red Gate\SQL Monitor backup so the original folder will be recreated (this is \ProgramDATA\ hidden folder not \Program files\  folder from 3 above)
5. Ensure that the actual SQLMonitor.exe installer file is not blocked (Right click the .exe -> Properties -> look for the "unblock" button or tickbox in the General tab of properties window and unblock it)
6. Run the .exe file explicitly as Administrator (Right click the exe -> Run as Administrator)