First, I would recommend making sure they are using the latest version (v23.0.32).
Next, go through the troubleshooting steps below:
Make sure Windows is up to date by going to the Windows Update section of your computer and telling it to "Check for Updates". Windows updates in batches so if it finds any you will want to do them, then go back and tell it to "Check for Updates" again, and repeat until it tells you there are none left after checking.
Verify Graphics Card and Driver
Another common source of this problem is if there is a problem with the video card or the driver is out of date. GibbsCAM is very graphics intensive and most crashes that occur are the result of the graphics processor the computer is using or the video card driver not being fully up to date.
You can check to see what graphics processor your computer is using by:
-Windows 10/11 - Display Settings->Advanced Display Settings->Display Adapter Properties
Check the "Adapter Type" your computer is using. It should be either an Nvidia or AMD card. If it shows Intel graphics it means your computer is not utilizing a dedicated video card, which is required.
If it shows a video card, click the "Properties" button, then go to the 'Driver' tab and check the "Driver Date". Make sure it is recent, usually within the past few months is good. If it is older you will want to go the manufacturer's website and download the latest driver for the card.
If there is a problem in the installation files of GibbsCAM you can try running the Recovery Tool. This will reset all your settings back to default and try to correct any problems in the software.
The Recovery Tool can be found in Windows 11 or 10 by going to the Start menu and doing a search for the name.
Each version of GibbsCAM you have installed has its own Recovery Tool, so make sure you run the one for the version of GibbsCAM you are using. Make sure GibbsCAM is closed when you run this tool.
You can also try doing a complete reinstall of the software by deleting the User Preferences again and uninstall via the Control Panel.
When you reinstall, please try temporarily disabling any anti-virus you have running in case that could be interfering with the install.
Also do NOT run the Migration Tool as it could potentially bring over corrupt settings files.