If you see a black screen during a screen sharing meeting, this may be due to the graphic card (eg Nvidia card) switching automatically.

How to fix 

1. Open the Nvidia Control Panel in the Windows Control Panel .
2. Click Manage 3D Settings
3. Click [ Program settings ] under [ Use the following 3D settings ].
4. [ Selection of customize program [under] Zoom Bin [from] directory Cpthost.exe to add a].
5. Click Add .
6. Find Cpthost.exe from the Zoom bin directory .
   (Located at C: > Users> YOURUSERNAME> AppData> Roaming> Zoom> bin)
7. Click Add Selected Program .
8. Select integrated graphic
9. Click Apply
10. Try Screen Sharing again with Zoom.