You can make the columns wider to read the reason why they can’t be scanned. Usually they can’t be scaned if:

  1. They have disable access
  2. They are in use in an odd way prevent any readout - sometimes it may happen that if a application uses a file than it makes the file inaccessible for any other application.

The only thing I’m concerned is the very big number of these files - usually I get about 2-5 of them for about 200 000 files on my hard drive. They mostly occur in temporary folders. Look at the files that couldn’t be read and see what they are and try to think of any reason why access to them could be totally danied.