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ThumbPrints Viewer™ and ThumbPrints Wiper™ let you view and remove thumbnail images from Windows.  Here's how to use them, what you can expect, and what you should not…


The Basics

A thumbnail is a small image made by Windows of the files you browse. Up to seven sizes are made of the first page of documents, spreadsheets, PDFs, the first frame of videos, text files, pictures, certain emails, and more. Windows does this to speed up previews the next time you browse a folder.  Although the name 'thumbnail' implies they are quite small, in fact these images can be large enough to read easily.


If your device is lost, stolen or hacked, your privacy is at risk because thumbnail images are not deleted when you delete the files from which they're made, nor are they wiped when you use a file-wiping app to permanently erase a file — they can remain for a long time, even permanently in some cases.


The Apps

ThumbPrints Viewer™ is a free app you can use to see all the thumbnail images Windows has made of files in your device.  You can get it here

If you discover that Windows has thumbnails of files you thought were long gone, and you want to get rid of them permanently, consider joining the Merlin community and get ThumbPrints Wiper™ to permanently destroy them (it's a free bonus that comes with the purchase of any premium Merlin version or any amount of extra Kahuna™ Traffic Credits).



Scanning for Thumbnails

Start ThumbPrints Viewer™ or ThumbPrints Wiper™ and simply press the button Scan my device

ThumbPrints will first look for what are called thumbcache.db files belonging to the current user, and then it will look for thumbs.db files in every folder of every fixed drive in your device.  This takes a while, so please be patient.

ThumbPrints categorizes what it finds in three sizes:

  • Large - thumbnails ranging in size from 256 pixels up to 2,048 pixels.
  • Medium - thumbnails larger than 96 and smaller than 256 pixels.
  • Small - thumbnails 96 pixels and smaller.

Thumbnails larger than 256 pixels are reduced to 256 pixels for display.  Additionally, if there are a very large number of big thumbnail images, ThumbPrints will show only the first couple thousand at the 256 pixel size.  After that, it will 'downshift' to show the rest at the 96 pixel size to avoid using too much memory on your device.

You can switch from images to a list by pressing the Show as List button (in the upper right corner) to see details about each thumbnail image, including the actual size in pixels of each thumbnail, and the thumbnail data file it's located in.


Important Points

ThumbPrints never copies or transmits what it discovers.  It just shows you what Windows still keeps in your device.  If you discover there are thumbnail images of files you thought were long gone, and you'd like to get rid of them, you can use ThumbPrints Wiper™ to get rid of it all. 

Windows evolves rapidly, and the way in which it protects its thumbnail files changes.  So to be sure of wiping as much as possible, it's very important to make sure you have the most recent version of ThumbPrints Wiper™. 


Wiping the Thumbnails

When you press the Wipe Thumbnails button, ThumbPrints Wiper™ urges you to close all other applications, including all Explorer windows.  This is important because other applications sometimes use thumbnail files, and if they have one open, it can be 'locked' in such a way that ThumbPrints Wiper™ can't get access to destroy them. 

Sometimes you may even have to restart your computer to get all those locks released, and then run only ThumbPrints Wiper™ so it can do the wiping.  Thereafter you can use your computer as you always do.


The destruction process takes between a few seconds and a few minutes, depending on how many thumbnail data files ThumbPrints Wiper™ finds and how big they are. The files are destroyed by overwriting their entire content using random data, and then deleting the file itself. 

Of course, if you browse to a particular folder again, Windows will recreate thumbnails of the files in it, but this will not include thumbnails of files you've already deleted. 

You can use ThumbPrints Wiper™ regularly to clean up your device, but this can become burdensome… why not just get Merlin and never have to worry about any of this again?


This is Just a Tool

ThumbPrints Wiper™ itself is not a permanent solution to the privacy risks created by Windows thumbnails, it's only a quick-fix that lets you peek at some of what Windows is really doing with your files, and remove the images Windows has made up to now. 


The real answer is to use Merlin, which encrypts everything and never leaves you exposed or wondering. But as a temporary measure, or as a prelude to importing your sensitive files into Merlin for real protection, ThumbPrints Wiper™ is a great little tool.




Frequently Asked Questions

What Windows versions does ThumbPrints support?

Both versions of ThumbPrints are certified to run on Windows 7, 8, 8.1 and 10.  


Is this just for Windows, or is there a ThumbPrints for iOS, Android or OS X?

So far it's only for Windows.  Android and iOS handle files in a very different way so they don't create the same kind of risk.  OS X (Mac desktops and laptops) does make thumbnail images, and we are developing an edition of ThumbPrints for OS X, which will also be available here on Merlin.World as soon as it's ready.


Should I turn off thumbnails in Windows Settings?

Probably not.  Although most versions of Windows allow you to turn off thumbnails, it severely cripples your browsing experience in Windows Explorer — you really do need to be able to view collections of files (especially pictures) as small images and see a preview of each one you select. 

If you still want to shut it off, go to the Folder Options Dialog in Windows Explorer, select the View tab, and then check the box Always show icons, never thumbnails.  Try that, and then browse your files for a few minutes and you'll see what we mean. 

We wish Microsoft offered a third option, something like: Show thumbnails, but don't cache (save) them.  This would be less efficient because the images would have to be reconstructed every time you open a folder, but nothing would be saved to a permanent file to later worry about.  Unfortunately, that option is not available.  It's interesting to speculate about why not.


Does ThumbPrints find thumbnails in folders copied from older devices?

Yes.  Both versions of ThumbPrints can find and display thumbnails in folders copied into newer versions of Windows from legacy systems such as Windows XP.


What should I do if it can't wipe everything?

If ThumbPrints Wiper™ reports that it could not wipe one or more thumbnail files, you'll find some helpful diagnostics here.


Why is ThumbPrints Viewer™ free?

We give it away because we want you to see for yourself just how much your privacy is at risk from thumbnail images or other things you might not even know exist.  And hopefully, after realizing that there is a genuine issue, you'll decide to return to our website to get one of our products. Merlin Essentials™ is free, and the premium version Merlin Prime™ is really inexpensive.  


Published on 2021-05-09 by:

Grasp the meaning not just the data.