Answered
When I minimize my GeoGebra while on a save file, a black screen appears on the GeoGebra window when I maximize it. It doesn't go away.
When I try to pull up a save, the CAS window won't appear even when I click on it.
The same question 
When I minimize my GeoGebra while on a save file, a black screen appears on the GeoGebra window when I maximize it. It doesn't go away.
When I try to pull up a save, the CAS window won't appear even when I click on it.
Looks like something related to your graphics card.
Try checking your GPU drivers, and updating them.
Please post a screenshot
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