title: macos Mojave beta - problem with image thumbnails
body: <p>Since I've upgraded to Mojave I keep having issues with image thumbnails. I simply can't see a thumbnails and what is instead is a bland placeholder. Is there any way to clear thumbnails cache, or solve this problem in any other way?</p>
  
  <p>What I've found is somewhere in here works for a few hours, and then the issue happened again. </p>
  
  <pre><code>sudo rm -rfv /Library/Caches/com.apple.iconservices.store; sudo find /private/var/folders/ \( -name com.apple.dock.iconcache -or -name com.apple.iconservices \) -exec rm -rfv {} \; ; sleep 3; sudo touch /Applications/* ; killall Dock; killall Finder
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/I6d4j.png" rel="nofollow noreferrer">preview</a> </p>