First, go to Control Panel \ Programs and Features
In this window, pay attention to: Corel Graphics Windows Shell Extension
If there are many of these items, please delete them all, if not, delete them manually by: Go to the directory:
C:\ Progam Files \ Common Files \ Corel \ Shared \ Shell Extension
Please delete all the directory: Shell Extension
Then go to Control Panel \ Programs and Features again
Right-click on Corel Graphics Windows Shell Extension and choose Uninstall
Then you restart your computer.
Next you go to drive C and find: ShellExt (usually it is located in: C:\ Progam Files \ Corel \ CorelDraw Graphics suite X… \ Setup \ CSG… \ ShellExt.msi)
Double click on ShellExt.msi to reinstall.
Then you restart your computer and now the corel files have shown the thumbnail icon for you.