Photos App - No Thumbnails

On my neighbour's machine (that I did a clean install on) when they load pictures from their camera, and the Photo app launches, all the photos/pictures shown in the Photo app are blank - i.e. the thumbnails are not showing. On this machine thumbnails are set to show and if you look at, for example, the Pictures folders all pictures are shown as thumbnails (via explorer). The set up of this machine is the same as mine and on my pc the Photo app icons do show as thumbnails. I have been trying to turn my Photo app thumbnail preview on and off but do not know how to do it. My logic being of I can turn thumbnails on and off in the Photo app I could get to the route of my neighbour's problem.

See if this tutorial be of any help
https://www.tenforums.com/tutorials/1...dows-10-a.html

Use Option One.

You might also have a look at these 2 tutorials :
How to Clear and Reset the Thumbnail Cache in Windows 10
https://www.tenforums.com/tutorials/5...dows-10-a.html

How to Rebuild the Icon Cache in Windows 10
https://www.tenforums.com/tutorials/5...dows-10-a.html