You can silently uninstall ArcGIS GeoEvent Server by running the msiexec.exe command.
- Open a command prompt.
- Execute one of the following commands to uninstall your version of ArcGIS GeoEvent Server:10.8.1
msiexec /x {C98F8E6F-A6D0-479A-B80E-C173996DD70B} /qb10.8msiexec /x {10F38ED5-B9A1-4F0C-B8E2-06AD1365814C} /qb