Issues like this can often be due to using outdated graphics drivers or an unsupported graphics card.
So first please check you are using one of the supported graphics cards listed HERE
If you are, please try updating your graphics drivers and ensure you have the latest available. Please see the links below to check.https://www.geforce.com/drivers
Also if your computer has switchable graphics, do ensure you are running iClone with the more powerful graphics card (Nvidia or AMD). Do not choose the Intel graphics option. You can normally do this by right-clicking the iClone 7 desktop icon and choosing "Run With Graphics Processor".
For more information on switchable graphics please check out the link below. This contains additional instructions on how to select the right graphics card option.
Please also run Windows Update to ensure your system is fully updated.
In Windows 10 go to Start > Settings > Update & Security > Windows Update and then "Check For Update".
Hopefully, this will help resolve the problem for you.