1001 indicates an InstallUtil error. Simply put, using installer class custom actions is an example of a fragile, out of process, reinventing the wheel anti-pattern. You should instead use Windows Installer’s built in service handling supported by InstallShield LE.
I hope this helps some of your sites encounter error 1001 when searching for a Windows .NET service using the InstallShield 2015 LE installer action with main output as the installer. This is a known bug after installing .NET 4.6 on Windows 10. Please don’t provide the same answer for multiple requests.
b Right-click the Windows Installer Help, then click Properties. c) If the Startup Type field is set to Disabled, change it to Manual. d) Click OK to close the actual properties window. Right-click the Windows Installer service and click Start. The service should start if there are no errors. F) Click on the “File” menu, then click on “Exit”.
Product: RMSEmailReader – Error 1001. Error 1001 An exception was thrown in the onafterinstall event handler for System.ServiceProcess.ServiceInstaller. –> The RMSEmailReader service cannot be started on machine “.”. –> The service did not respond to really quickly respond to a start or control request.
How to fix InstallShield error 1001 when installing custom Windows?
Select the menu item that appears to actually add the service and you will be presented with a form allowing you to set up a detailed installer. Once you do this and rebuild your MSI family, it will most likely fix error 1001. This can be a terrible waste of time that the original InstallShield developers could have solved. Unhappy. @daylight Thank you.
How to fix InstallShield error 1001?
Method 1: Rename the InstallShield folder. Right-click the InstallShield folder and navigate to Rename.
How do I fix error 1001 The specified service already exists?
msi”), you may also get the confusing error message “Error 1001: The specified service already exists” when reinstalling. This means that the plugin must be manually uninstalled by the update service. To uninstall the service To do this: Elevated Command Prompt, enter: SC DELETE PluginUpdaterService.
How to deal with ” error 1001.the specified service already exists “?
The ServiceInstaller doesn’t know how many references there will be for the service, so the code is essentially trying to reinstall it rather than incrementing the references. It is mentioned here:

Ermias is a tech writer with a passion for helping people solve Windows problems. He loves to write and share his knowledge with others in the hope that they can benefit from it. He’s been writing about technology and software since he was in college, and has been an avid Microsoft fan ever since he first used Windows 95.