I half wonder if the first time you ran it then it mostly removed everything but there was a running process which prevented some files from deleting (we use install4j and I don't know how well it copes in that case). The second time you run it, the uninstaller is looking for some stuff and it is gone?

I uninstall every version to install the next version on win7 (64bit) and it always works so I am just trying to come up with a plausible scenario?

I couldn't find the source of the problem, so I manually deleted the folder with the JRuby distribution and remove the branch HKEY_CURRENT_USER\Software\RubyInstaller from the Windows register. Then I again installed the same version of JRuby. The package was installed without any problems, however, when I tryed to uninstall it I got the same errors.

Thanks for replying back with that feedback.

I am not sure I have any idea how we can reduce this more but at least it sounds like my simple theory was easily proven wrong. We install into C: (like MRI ruby installers) to bypass security restrictions on saving files to our install dir. Perhaps you have a slightly more locked down system? I doubt it since you can install ok, but I am just brainstorming :)

Thank you, for support. Although we couldn't resolve the problem, we established that first: it has a certain relation to security restrictions (or issues) of my system, and second: it somewhat connected with how install4j works inside these restrictions. Anyway, it doesn't have much to do with JRuby itself.

That's true but I should look into getting a newer version of install4j setup. We are not on current major release. Perhaps they address something?

closing this due to lack of activity. Summary seems to be that our installed runtime does not uninstall in some restricted env (meaning an env which is more locked down than what a default win installation would be). We do not know what was locked down and so we cannot really try to fix this.