In the Product Components list, find the entry for ArcGIS Pro 2.8. Click the Download button. This will save the installer executable ( .exe ) to your computer [21†L22-L23].
You are trying to install Patch 8 on an older version (e.g., 2.7 or 2.6) or a newer version (3.0). Solution: Ensure you have exactly 2.8.x base version installed. arcgis pro 2.8 patch 8 -2.8.8- download