1 files changed, 1 insertions, 1 deletions

diff --git a/src/internal/WixInternal.TestSupport/ExternalExecutable.cs b/src/internal/WixInternal.TestSupport/ExternalExecutable.cs
index e0345dfb..9effd843 100644
--- a/src/internal/WixInternal.TestSupport/ExternalExecutable.cs
+++ b/src/internal/WixInternal.TestSupport/ExternalExecutable.cs
@@ -195,7 +195,7 @@ namespace WixInternal.TestSupport
                     sb.Append(' ');
                 }
 
-                if (arg.IndexOf(' ') > -1)
+                if (arg.IndexOf(' ') > -1 && !arg.EndsWith("\""))
                 {
                     sb.Append("\"");
                     sb.Append(arg);