I get a dialog saying my installer is from an “Unknown Publisher” on Windows XP. How can I get rid of this?
You have to sign the executable.
Cas 
But how do I do this?
I remember reading something vaguely similar about some kind of Mac OS X files (probably .app), but you had to pay Apple to get a certificate to sign your files with.
This whole thing is a new idea to me; I don’t remember getting this message until recently. I assume it’s a new thing with Windows XP SP 3.
You need to find a nice cheap certificate authority who Microsoft are friendly with - I can’t unfortunately remember off the top of my head which ones are, and I went for a relatively expensive one, Thawte - and generate a certificate signing request using some free tools that come with MS dev tools or I think the JDK ones will do it too.
Then you use the MS devkit tools to sign the executable with the certificate that the certificate authority sends back to you. It costs money. You need to be verifiably a company or organisation as well. Otherwise you’ll be using a free certificate which still puts up a scary(ish) dialog.
Cas
Ok, I found a way around it. Just put the setup file in a .zip file. Then, after you extract it, you won’t get the dialog.
Of course, if you do that, there will always be people who won’t be able to figure out how to extract the .exe from the .zip file.
I looked up Thawte, and it’s way too expensive. The cost for one year is more than the total amount of money I’ve made from selling games. Maybe I’ll get the certificate when I have more games to sell.
My plan is to hope that people are used to getting the stupid dialog and don’t care about it any more.
On the one hand, I might sell more copies of my games if the .exe’s were signed. On the other hand, the reasons why people don’t buy my games are the following:
- They’re not incredibly original and aren’t big beautiful masterpieces.
- No one knows they exist anyways.
So, for the time being, I won’t worry about the certificate.
Edit: Fixed spelling error.