I'm having a problem with managed properties. I've made a custom web part to do a people search / keywordQuery based on user properties/managed metadata. I had to change a managed property to map to a different crawled property, because the previous mapping was wrong. I then did a full crawl. The problem is that now, the property contains both new (correct) and old (incorrect) data. I guess I could do an index reset, but this seems to be a bad solution, since this (I think) will make the search unavailable, and could take some time. I guess I'm afraid to "break" something. Is there an easier, safer way of correcting the returned search values, other than resetting the entire index? I am using Fast search.
If a full crawl / incremental crawl doesn't do it then, do the index reset out of hours. If you can, and then a full crawl. It will mean your search is down for a short period but only the length of a full crawl.