Settings changes are normally saved automatically, could you try running XnView Classic with Admin rights and report if that solves the problem?
Which version of XnView Classic and which version of Windows are you using?
If running with Admin rights doesn't solve the problem, there may possibly be an issue with your ini file location, as there may have been a similar report recently which I think XnTriq
has been investigating?
This is the recent thread I was thinking of: XnView 2.39 forgot the settings on Win7
, I don't know if that is any help?