fcremove.exe is a specialized utility provided by Fortinet (often found within the FortiClient installation directory or the FortiClientTools package). Unlike the GUI uninstaller, this executable runs from the Command Prompt and can forcibly remove FortiClient components, registry keys, and residual files that often cause "corrupted installation" errors.
(If the file isn’t there, copy it from the extracted installer folder) forticlient fcremove.exe