diff --git a/src/NTwain/TwainSessionInternal.cs b/src/NTwain/TwainSessionInternal.cs
index aba78d9..1715707 100644
--- a/src/NTwain/TwainSessionInternal.cs
+++ b/src/NTwain/TwainSessionInternal.cs
@@ -276,7 +276,9 @@ namespace NTwain
 
                 // In any event the trick to get this thing working is to return from the callback first
                 // before trying to process the msg or there will be unpredictable errors.
-                _msgLoopHook?.BeginInvoke(() =>
+
+                // changed to sync invoke instead of begininvoke for hp scanjet, not sure if will break other scanners :(
+                _msgLoopHook?.Invoke(() =>
                 {
                     HandleSourceMsg(msg);
                 });