I performed a search through 939 PDF files using the expression:
(transition NEAR education) OR (LIKE transicao NEAR LIKE educacao)
The files listed in the result were narrowed down to 309.
The screenshot:

However I am concerned with the "warnings generated during search".
I realized a couple of files listed in the "warnings" (not included in the main list of the search result) do fit the search criteria. I mean, the files seems to be neglected/missed by FileLocator (false negative).
I realized the problem through two process:
1- From the same search window (without change any criteria) I just click on the button "start" and the results of the search included the neglected/missed file. I did it a couple of times, being sometimes the same file was considered in the result, and other times it was neglected/missed as a "warning".
2- To double check I created a new search having selected the file in "look in", so just it was searched. The result listed the file and in the tab "hits" the expected text was presented.
Is there any setting in FileLocator to provide more accuracy in the search in order to avoid "warnings" (false negatives) of files which should be included in the result?
Any other tip to handle "warnings generated during search"?