diff --git a/proxy.go b/proxy.go
index 5c9a598..a42f6e3 100644
--- a/proxy.go
+++ b/proxy.go
@@ -247,22 +247,31 @@ func (p *Proxy) sendCommand(b []byte, waitPrompt ...bool) ([]byte, error) {
 	}
 
 waitLoop:
+	for {
+		// wait until received prompt
+		bytesOut := <-p.stdout
+		debug(string(bytesOut))
+		parts := bytes.Split(bytesOut, []byte("\n"))
+		for _, part := range parts {
+			if isPrompt(part) {
+				break waitLoop
+			}
+		}
+
+		output = append(output, bytesOut...)
+	}
+
+	// drain error channel
+errLoop:
 	for {
 		select {
 		case bytesErr := <-p.stderr:
-			debug(string(bytesErr))
-			err = fmt.Errorf("%s", string(bytesErr))
-			break waitLoop
-		case bytesOut := <-p.stdout:
-			debug(string(bytesOut))
-			parts := bytes.Split(bytesOut, []byte("\n"))
-			for _, part := range parts {
-				if isPrompt(part) {
-					break waitLoop
-				}
+			if len(bytesErr) > 0 {
+				debug(string(bytesErr))
+				err = fmt.Errorf("%s", string(bytesErr))
 			}
-
-			output = append(output, bytesOut...)
+		default:
+			break errLoop
 		}
 	}
 
diff --git a/proxy_test.go b/proxy_test.go
index 325d879..3d171f5 100644
--- a/proxy_test.go
+++ b/proxy_test.go
@@ -2,19 +2,25 @@ package inkscape
 
 import (
 	"fmt"
+	"os"
 	"testing"
 )
 
 func TestConcurrent(t *testing.T) {
 	tempFiles := make([]string, 0)
-	// defer func() {
-	// 	for _, t := range tempFiles {
-	// 		os.Remove(t)
-	// 	}
-	// }()
+	defer func() {
+		for _, t := range tempFiles {
+			os.Remove(t)
+		}
+	}()
 
 	proxy := NewProxy(Verbose(true))
-	proxy.Run()
+	err := proxy.Run()
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+	defer proxy.Close()
 
 	for i := 0; i < 10; i++ {
 		temp := fmt.Sprintf("%d.pdf", i)
@@ -27,3 +33,21 @@ func TestConcurrent(t *testing.T) {
 		}()
 	}
 }
+
+func TestOpenFail(t *testing.T) {
+	proxy := NewProxy(Verbose(true))
+	err := proxy.Run()
+	if err != nil {
+		t.Error(err)
+		t.FailNow()
+	}
+	defer proxy.Close()
+
+	res, err := proxy.RawCommands("file-open:notexists.svg")
+	if err == nil {
+		t.Error("should fail", string(res))
+		t.FailNow()
+	}
+
+	t.Log(string(res))
+}