Is it safe to shut down Mac while Spotlight is still indexing? Had some issues with Finder and Spotlight not finding files. Used the instructions to rebuild Spotlight index in Mac. Put entire Macintosh HD there. Checked and now it seems to find all the files again, but mdworker files are still active in Activity Monitor.

It has been almost 7 hours and I can't keep Mac going anymore.

My question is - could there be any damage or security risk if Spotlight is interrupted indexing everything? For example, would some important system files not find their data to function properly?

Does Mac's OS itself use Spotlight index for its own work or is it purely for user?
could there be any damage or security risk if Spotlight is interrupted
  indexing everything?


No.




  Is it safe to shut down Mac while Spotlight is still indexing?


Yes.