We noticed yesterday that we're having some issues when searching for documents by fields/templates.  They are either showing no results from the search criteria or not returning nearly as many as there should be.  We're thinking we are having some indexing issues and wondering if the best solution is to reindex the entire repository or if we can go a different route?  If so, what do those steps look like?  Anything we should check before doing so?  It's rather large and I know there are many deciding factors on this, but is there any sort of average of how long it might take?  This repo is approx. 3.7 TB. 

I came across another thread, they mentioned that after you click the delete button, "go to the directory shown in the path and make sure no files are still in the directory".  Any idea what they meant by that?  Any help or guidance on this would be greatly appreciated.