After running the design thumbnails repairing utility file, still no design thumbnails showing up for some specific design file format.
First of all, make sure the setting of "Always show icons, never thumbnails" is not ticked in File Explorer > Options. If it is not the case, then continue with the measure below:
The current file thumbnails must be cleaned up. So, Hatch software can regenerate the design thumbnails for all of the supported design files.
1) Run cmd with "Run as administrator"
i) in case you have Windows 10,
a) right click on the Windows “Start” button
b) in the right click menu, click on “Command Prompt (Admin)” menu
c) click on OK button in the warning message to allow it to run
ii) in case you have Windows 7 or 8.1
a) in Windows run box, type: cmd
b) under Programs, right click on “cmd”
c) in the right click menu, click on “Run as administrator”
2) In the Command Prompt box, type the command line (you may copy and paste it):
Note: it will open PC cleaning up dialog box.
3) Click OK button to continue.
Note: When it is finished, restart Hatch software.
4) in Hatch software, create an object
5) Export the design to that design file format
6) in "My Designs", browsed the design file that is exported in the step 6)
Note: Design Thumbnail should show up. Browse other design files of the same file format, and Design Thumbnails should be back one by one.