diff --git a/project/Scripted.scala b/project/Scripted.scala
index 163b3223c..aa3e55db6 100644
--- a/project/Scripted.scala
+++ b/project/Scripted.scala
@@ -72,7 +72,7 @@ object Scripted {
     val loader = classpath.ClasspathUtilities.toLoader(scriptedSbtClasspath.files, noJLine)
     val bridgeClass = Class.forName("sbt.test.ScriptedRunner", true, loader)
     val bridge = bridgeClass.newInstance.asInstanceOf[SbtScriptedRunner]
-    val launcherVmOptions = Array("-XX:MaxPermSize=256M") // increased after a failure in scripted source-dependencies/macro
+    val launcherVmOptions = Array("-XX:MaxPermSize=256M", "-Xmx1G") // increased after a failure in scripted source-dependencies/macro
     try {
       // Using java.util.List to encode File => Unit.
       val callback = new java.util.AbstractList[File] {