Between 91% and 92% System Ninja will clean the Windows Temps directory (C:\Users\
It’s possible that a corrupt file is causing problems while scanning this area. It could also be a huge number of files in one of those directories are choking System Ninja as it tries to scan.
I would suggest manually navigating to these directories and cleaning out the files.
The most likely offender is the thumbnail caches, so it may be worth unchecking the ‘Thumbnail Caches’ option and seeing if that fixes it. Please confirm if this does indeed resolve the problem so we can investigate possible fixes.