I'd like to know too, the link from Rajshree doesn't work for me.
I have a folder that I previously worked on, picking only some people for FR. Now I want to go back and force a search for all the other faces but can't. What's the trick?
It appears that there is no immediately apparent way to force LR to reindex by folder or filmstrip of selection. You need to go back and manually redraw a facebox for tagging by person. Major drag.
I've been indexing by year in my catalog and hit a major glitch in 2015 where I lost/deleted indexing for several hundred images per person. No way I'm manually going back!
See feedback on this thread for reverting to LR5 catalog and recreating LR6 workaround (if you could call it that). Any comments from Adobe??. How to reindex facial recognition data in LR 6?
Major issue here. I accidently deleted some of the already recognized persons and there is no way that I could manually draw a box around hundreds of people again manually.
How can this issue have slipped by Adobe? They must have thought of this during development!?
A reindex feature must be implemented ASAP!
The face recognition is useless if there is no way to undo or reindex…
This is a user-to-user forum in which Adobe rarely participates. Please add your vote and opinion to this topic in the official Adobe feedback forum: Lightroom 6/CC - Allow facial recognition feature to re-index a folder/collection