I always set mine to read only once tweaked for that reason. Happened to me before too.I'm still annoyed my INI settings got reset when I put a new GPU in without having the latest version backed upI'd managed to get perfect settings for rendering proper detail trees in density to the horizon, high level of active grids without crashes or mission bugs and without odd rendering issues on distant mountains, etc.
and now I can't replicate them.
I'd managed to get perfect settings for rendering proper detail trees in density to the horizon, high level of active grids without crashes or mission bugs and without odd rendering issues on distant mountains, etc. 

. Pleasantly surprise already got the SE so must have got the upgrade in the past. Might fire it up to give it another bash. Thanks for the info.