.Net Windows Services and InstallState file - is it really needed?

Question

I've got a number of managed code Windows Services for which we use the Frameworks InstallUtil tool to install into the service control manager. This tool creates a new file at install time with an extension of .InstallState. I have experimented with deleting this file and an uninstall still works fine afterwards.

So my questions is, what is this file for and is there any reason I shouldn't delete it?

Edit 5/3/10: Really? Nobody has any clue what the value of this file is?

Answer 1

In VS.NET you can define a custom dialog for your msi project, I am using such a dialog to ask for the SQL Server address and credentials, the msi stores all the info from the textboxes into InstallState file. When the service is uninstalled it will read the values from InstallState file and will drop the database created in the install phase. In my case InstallState file is a must because the uninstall will fail if the file was deleted after install.

Answer 2

The InstallState file is used by InstallUtil.exe for uninstalling the service/assembly. The data contained within it is uninstall data only. If you haven't read the short obscure reference on MSDN, you can read it here.

Maybe a setup package uninstalls everything for you correctly but I'm not sure if a service would uninstall properly if you were calling InstallUtil by hand/script yourself.

That's the supposed value of a .InstallState file.

Answer 3

The file should be deleted by the uninstall process. If you are using a custom install action you should add it the uninstall process as well. A missing .installstate file will not prevent the service from being uninstalled.

http://adamhouldsworth.blogspot.com/2009/11/c-setup-installstate.html

http://support.microsoft.com/kb/934388