User Time is the percentage of elapsed time the processor spends in the user mode. User mode is a restricted processing mode ...

% User Time is the percentage of elapsed time the processor spends in the user mode. User mode is a restricted processing mode designed for applications, environment subsystems, and integral subsystems.  The alternative, privileged mode, is designed for operating system components and allows direct access to hardware and all memory.  The operating system switches application threads to privileged mode to access operating system services. This counter displays the average busy time as a percentage of the sample time.