The help file/FAQ says:
So it should eliminate the mess that you see.
You may well have to reindex. But if that is what it takes to fix your problem, there is not other choice.
The rest of your questions are beyond my knowledge.
The issue of accents is a long running one with X1. You may find it worthwhile to search the forum for earlier discussions.
Do you always see this behaviour? Is it in all files, email and documents? If it is only occasional, then maybe it is down to the fonts and what you have installed on the PC.