Assets (or shelf) previews are empty
This issue can be caused by other software, see: Software conflicts.
If it is impossible to determine which software updating/uninstalling, look for an environment variable named "QT_PLUGIN_PATH" and remove it.
- Open System in Control Panel.
- On the Advanced tab, click Environment Variables
- Look for the variable named "QT_PLUGIN_PATH"
- Remove it
- Restart your computer