I had to rewrite the Spotlight Index a long time ago for reasons I've forgotten. The memory on my hard drive went from 300GB to about 150GB and I was losing about 1GB every 5 minutes. We then wanted to rebuild the Spotlight index using only files from a single user, so we excluded quite a few files. The same thing happened, but this time the space on my computer was down to 25GB and continuing to shrink. So I can't index my files and search for something. Otherwise, there will be no memory on my hard disk.