I keep loosing my settings in Excel. Periodically, my toolbars reset back to
defaults and my custom toolbars are gone. Also, my custom colors I set in
Tools|Options often resort back to defaults.

What could be causing this and what can I do to prevent it?

What's the easiest and cleanest way to back up these settings and then
reapply them when needed?

What file keeps the color settings?

Thanks.