today I was going mad because my changes in xnview.ini did not show effect
I triple checked in options that ini is stored in XnView's folder (where I edited). I wondered that text editor did not show changes in ini after option change but those changes were persisted as they were still working after XnView close & restart 
Finally I searched the whole hard drive for a file xnview.ini and found one more in "C:\Users\Georg\AppData\Roaming\XnView" (georg is my windows user name). I tried and that was the one XnView really used... The same happened for category.db and XnView.db. I found a solution that "xnview folder" is shown AND really used by starting XnView, options, set "user folder" as storage for INI etc, close & restart XnView, options, and now: not user folder, but XnView folder was shown (!!) and also really used. Since then, "C:\Users\Georg\AppData\Roaming\XnView" was not used by XnView any more, but category.db and XnView.db are in "C:\Users\Georg\AppData\Local\VirtualStore\Program Files (x86)\XnView" Here, the same trick helped: Set cache dir to user, close XnView, start it again, set it to xnview folder, done.The same happened for XnViewMP, too.
I did not install/setup XnView, but extracted the downloaded ZIP, moved it to a directory, started it, selected "use .ini file in application folder" in configuration wizard. I can now only reproduce the behaviour that "C:\Users\Georg\AppData\Roaming\XnView" is created but not that also all user files are created there.
It happened on Windows 7 64bit RC1 German. It sometimes ask whether a program is installed correctly, but I cannot recall it did so with XnView - but at least there is some kind of check for installations.
/Georg