Sometimes, when we try to search for a file and we don't get a result. We thought that file is not available on the site or may be search crawl will take sometime to crawl it.
File is uploaded and checked in into SharePoint even search crawl is idle. Still no search result.
If you check crawl logs you can see that the file has been deleted by gatherer.
1. Do an index reset.
2. Do a Full Crawl on local SharePoint site content source.
This help the file or content to get back in the index.
Hope it helps:)
Happy SharePointing :)