diff --git a/runner.go b/runner.go
index 8bd0a34..db24a7c 100644
--- a/runner.go
+++ b/runner.go
@@ -2,6 +2,7 @@ package process
 
 import (
 	"context"
+	"fmt"
 	"sync"
 	"time"
 
@@ -257,13 +258,25 @@ func (r *Runner) runSpec(ctx context.Context, spec RunSpec) RunResult {
 
 	<-proc.Done()
 
+	var runErr error
+	switch proc.Status {
+	case StatusKilled:
+		runErr = coreerr.E("Runner.runSpec", "process was killed", nil)
+	case StatusExited:
+		if proc.ExitCode != 0 {
+			runErr = coreerr.E("Runner.runSpec", fmt.Sprintf("process exited with code %d", proc.ExitCode), nil)
+		}
+	case StatusFailed:
+		runErr = coreerr.E("Runner.runSpec", "process failed to start", nil)
+	}
+
 	return RunResult{
 		Name:     spec.Name,
 		Spec:     spec,
 		ExitCode: proc.ExitCode,
 		Duration: proc.Duration,
 		Output:   proc.Output(),
-		Error:    nil,
+		Error:    runErr,
 	}
 }
 
diff --git a/service.go b/service.go
index 6602f3e..ee80a32 100644
--- a/service.go
+++ b/service.go
@@ -224,7 +224,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 				ID:       id,
 				ExitCode: -1,
 				Duration: time.Since(startedAt),
-				Error:    nil,
+				Error:    err,
 			})
 		}
 		return nil, coreerr.E("Service.StartWithOptions", "failed to start process", err)
@@ -283,7 +283,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 		err := cmd.Wait()
 
 		duration := time.Since(proc.StartedAt)
-		status, exitCode, _, signalName := classifyProcessExit(err)
+		status, exitCode, exitErr, signalName := classifyProcessExit(err)
 
 		proc.mu.Lock()
 		proc.Duration = duration
@@ -301,7 +301,7 @@ func (s *Service) StartWithOptions(ctx context.Context, opts RunOptions) (*Proce
 			ID:       id,
 			ExitCode: exitCode,
 			Duration: duration,
-			Error:    nil,
+			Error:    exitErr,
 		}
 
 		if c := s.coreApp(); c != nil {
@@ -629,7 +629,8 @@ func classifyProcessExit(err error) (Status, int, error, string) {
 			}
 			return StatusKilled, -1, coreerr.E("Service.StartWithOptions", "process was killed", nil), signalName
 		}
-		return StatusExited, exitErr.ExitCode(), nil, ""
+		exitCode := exitErr.ExitCode()
+		return StatusExited, exitCode, coreerr.E("Service.StartWithOptions", fmt.Sprintf("process exited with code %d", exitCode), nil), ""
 	}
 
 	return StatusFailed, 0, err, ""
diff --git a/service_test.go b/service_test.go
index 08c7332..90a57f2 100644
--- a/service_test.go
+++ b/service_test.go
@@ -327,7 +327,7 @@ func TestService_Actions(t *testing.T) {
 		defer mu.Unlock()
 		assert.Len(t, exited, 1)
 		assert.Equal(t, proc.ID, exited[0].ID)
-		assert.Nil(t, exited[0].Error)
+		assert.Error(t, exited[0].Error)
 		assert.Equal(t, StatusKilled, proc.Status)
 	})
 
@@ -360,7 +360,7 @@ func TestService_Actions(t *testing.T) {
 		defer mu.Unlock()
 		require.Len(t, exited, 1)
 		assert.Equal(t, -1, exited[0].ExitCode)
-		assert.Nil(t, exited[0].Error)
+		assert.Error(t, exited[0].Error)
 	})
 }