There is a bug in Sierra but might be all MacOS where some process keeps deleting my Spotlight index file. tens of thousands of file that get indexed and it uses a lot of battery when I'm mobile. I can't use the laptop because I can't rely on it keeping the index. If I turn the indexing off while on battery, I can't use the indexing. In all of the years I've used Windows, I've never had a problem of the indexing file being deleted. It keeps happening under Sierra. Is there some way to lock the file so that it can be modified but not deleted by the OS?