Videos not Showing Thumbnails, QuickTime Icon Appearing Instead

Sometimes your video previews on your Mac may show a QuickTime icon instead of the video thumbnail. Video thumbnails are still images that provide a preview of your video. When you see a video’s thumbnail, it will give you small details and help you recognize the video and remember what it is about; they are like a book cover, thus it is important that the thumbnails show correctly. In this article, I explain what you can do so that your videos are not showing the generic, placeholder QuickTime icon.

Finder has a built-in feature called Quicklook that gives you thumbnail previews of videos along with other types of files.

This issue probably occurs due to Quicklook cache problems. Here is how you can address those cache issues.

Quit the Quicklook Thumbnail Agent

Let’s do this first: We will force quit (restart) the process called Quicklook Thumbnails Agent and hopefully this will cause the correct thumbnails to appear again. Follow these steps:

  1. On your Mac, open the Activity Monitor. Open the Applications folder, then the Utilities folder and double-click Activity Monitor. You can also just open Spotlight Search using Command (⌘)Space Bar and start typing Activity Monitor.
Activity Monitor
  1. Copy the following process and paste it into the Activity Monitor’s search field:
com.apple.quicklook.ThumbnailsAgent
Thumbnail process
  1. Highlight the process in the main part of the window by clicking on it. Click the (X) stop icon and then click Force Quit.
Force quit
  1. This will quit the Thumbnails Agent process. Close Activity Monitor. After that, restart Finder. To restart Finder, press and hold the Option key while right-clicking (or control-clicking) on the Finder icon in your Dock. Select Relaunch.
Relaunch the Finder
  1. Just to cover everything, restart your Mac too. After your Mac restarts, check a video to see if its thumbnail appears.

Hopefully, your thumbnails are working now, but if not, let’s clear the cache.

Clear Quick Look cache

If force quitting didn’t work, let’s try clearing the cache next. Here is how:

  1. Open Terminal on your Mac. Again, go to Applications > Utilities in Finder, or open Spotlight Search with Command (⌘)Space Bar and type Terminal.
  2. In Terminal, enter the following command and hit enter:
qlmanage -r cache
  1. Terminal will tell you if the command executed (see the screenshot below):
qlmanage: call reset on cache
Clear Quick Look cache
  1. This will reset the cache quickly. Of course, how quickly depends on the size of your cache.

In general, most thumbnail problems can be fixed by clearing the cache. Hopefully, following the steps above cleared the cache, and your thumbnail problems too.

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Dr. Serhat Kurt worked as a Senior Technology Director. He holds a doctoral degree (or doctorate) from the University of Illinois at Urbana / Champaign and a master’s degree from Purdue University. Here is his LinkedIn profile.

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