diff --git a/launch/Provider.scala b/launch/Provider.scala
index 69d93f751..365c2b2d4 100644
--- a/launch/Provider.scala
+++ b/launch/Provider.scala
@@ -15,21 +15,32 @@ trait Provider extends NotNull
 	def parentLoader: ClassLoader
 	def lockFile: File
 
+	def retrieveFailed: Nothing = fail("")
+	def retrieveCorrupt(missing: Iterable[String]): Nothing = fail(": missing " + missing.mkString(", "))
+	private def fail(extra: String) =
+		throw new xsbti.RetrieveException(versionString, "Could not retrieve " + failLabel + extra)
+	private def versionString: String = target match { case UpdateScala => configuration.scalaVersion; case a: UpdateApp => Version.get(a.id.version) }
+
 	val (jars, loader) = Locks(lockFile, new initialize)
 	private final class initialize extends Callable[(Array[File], ClassLoader)]
 	{
 		def call =
 		{
 			val (existingJars, existingLoader) = createLoader
-			if(Provider.needsUpdate(existingLoader, testLoadClasses))
-			{
-				( new Update(configuration) )(target)
-				val (newJars, newLoader) = createLoader
-				Provider.failIfMissing(newLoader, testLoadClasses, failLabel)
-				(newJars, newLoader)
-			}
-			else
+			if(Provider.getMissing(existingLoader, testLoadClasses).isEmpty)
 				(existingJars, existingLoader)
+			else
+			{
+				val retrieveSuccess = ( new Update(configuration) )(target)
+				if(retrieveSuccess)
+				{
+					val (newJars, newLoader) = createLoader
+					val missing = Provider.getMissing(newLoader, testLoadClasses)
+					if(missing.isEmpty) (newJars, newLoader) else retrieveCorrupt(missing)
+				}
+				else
+					retrieveFailed
+			}
 		}
 		def createLoader =
 		{
@@ -48,13 +59,9 @@ object Provider
 	{
 		def accept(file: File) = !file.isDirectory && file.getName.endsWith(".jar")
 	}
-	def failIfMissing(loader: ClassLoader, classes: Iterable[String], label: String) =
-		checkTarget(loader, classes, (), missing => error("Could not retrieve " + label + ": missing " + missing.mkString(", ")))
-	def needsUpdate(loader: ClassLoader, classes: Iterable[String]) = checkTarget(loader, classes, false, x => true)
-	def checkTarget[T](loader: ClassLoader, classes: Iterable[String], ifSuccess: => T, ifFailure: Iterable[String] => T): T =
+	def getMissing(loader: ClassLoader, classes: Iterable[String]): Iterable[String] =
 	{
 		def classMissing(c: String) = try { Class.forName(c, false, loader); false } catch { case e: ClassNotFoundException => true }
-		val missing = classes.toList.filter(classMissing)
-		if(missing.isEmpty) ifSuccess else ifFailure(missing)
+		classes.toList.filter(classMissing)
 	}
 }
\ No newline at end of file
diff --git a/launch/Update.scala b/launch/Update.scala
index 7857b107a..30a70ecd2 100644
--- a/launch/Update.scala
+++ b/launch/Update.scala
@@ -51,17 +51,18 @@ final class Update(config: UpdateConfiguration)
 	private lazy val ivy = Ivy.newInstance(settings)
 
 	/** The main entry point of this class for use by the Update module.  It runs Ivy */
-	def apply(target: UpdateTarget)
+	def apply(target: UpdateTarget): Boolean =
 	{
 		Message.setDefaultLogger(new SbtIvyLogger(logWriter))
 		ivy.pushContext()
-		try { update(target) }
+		try { update(target); true }
 		catch
 		{
 			case e: Exception =>
 				e.printStackTrace(logWriter)
 				log(e.toString)
 				System.out.println("  (see " + logFile + " for complete log)")
+				false
 		}
 		finally
 		{
diff --git a/launch/interface/src/main/java/xsbti/RetrieveException.java b/launch/interface/src/main/java/xsbti/RetrieveException.java
new file mode 100644
index 000000000..f9975b809
--- /dev/null
+++ b/launch/interface/src/main/java/xsbti/RetrieveException.java
@@ -0,0 +1,12 @@
+package xsbti;
+
+public final class RetrieveException extends RuntimeException
+{
+	private final String version;
+	public RetrieveException(String version, String msg)
+	{
+		super(msg);
+		this.version = version;
+	}
+	public String version() { return version; }
+}
\ No newline at end of file
diff --git a/launch/src/main/resources/sbt/sbt.boot.properties b/launch/src/main/resources/sbt/sbt.boot.properties
index 561d0f76c..e43653655 100644
--- a/launch/src/main/resources/sbt/sbt.boot.properties
+++ b/launch/src/main/resources/sbt/sbt.boot.properties
@@ -31,8 +31,8 @@
  project.name: quick=set(test), new=prompt(Name), fill=prompt(Name)
  project.organization: new=prompt(Organization)
  project.version: quick=set(1.0), new=prompt(Version)[1.0], fill=prompt(Version)[1.0]
- def.scala.version: quick=set(2.7.5), new=set(2.7.5), fill=set(2.7.5)
+ def.scala.version: quick=set(2.7.7), new=set(2.7.7), fill=set(2.7.7)
  build.scala.versions: quick=set(2.7.7), new=prompt(Scala version)[2.7.7], fill=prompt(Scala version)[2.7.7]
- sbt.version: quick=set(0.6.3), new=prompt(sbt version)[0.6.3], fill=prompt(sbt version)[0.6.3]
+ sbt.version: quick=set(0.6.6), new=prompt(sbt version)[0.6.6], fill=prompt(sbt version)[0.6.6]
  project.scratch: quick=set(true)
  project.initialize: quick=set(true), new=set(true)
\ No newline at end of file
diff --git a/project/build.properties b/project/build.properties
index 3a7ca66b1..4a35c1583 100644
--- a/project/build.properties
+++ b/project/build.properties
@@ -1,5 +1,7 @@
+#Project properties
+#Sun Dec 06 21:33:35 EST 2009
 project.organization=org.scala-tools.sbt
 project.name=xsbt
 sbt.version=0.5.6
-project.version=0.6.5
-scala.version=2.7.5
+project.version=0.6.6
+scala.version=2.7.7