The process or restoring the Windows photo viewer is different if you Upgraded to Windows 10 or did clean install. This tutorial will show you how to restore Windows Photo Viewer whether you upgraded or clean installed Windows 10.
Option 1 – Restore Windows Photo Viewer from an upgrade:
1. Click on start button then type “Default Programs” and select it form the results.
2. Then click on Set your default programs.
3. On the left pane under programs scroll down to select Windows photo viewer, then click on Set this program as default.
Option 2 – Restore Windows Photo Viewer from a clean Install:
1. Download and extract the Restore Windows Photo Viewer.reg zip file.
2. Double click on the downloaded .reg file to merge it.
3. If prompted, click on Run, Yes to the (UAC), Yes, and OK to any warmnings to approve the merge.
4. Delete the downloaded .reg file from the extracted location.
5. If you restored Windows Photo Viewer, you can now set this program as default.