diff --git a/main/actions/src/main/scala/sbt/ForkTests.scala b/main/actions/src/main/scala/sbt/ForkTests.scala
index 0217f1422..ee6ed1913 100755
--- a/main/actions/src/main/scala/sbt/ForkTests.scala
+++ b/main/actions/src/main/scala/sbt/ForkTests.scala
@@ -11,7 +11,7 @@ import Tests.{Output => TestOutput, _}
 import ForkMain._
 
 private[sbt] object ForkTests {
-	def apply(runners: Map[TestFramework, Runner],  tests: List[TestDefinition], config: Execution, loader: ClassLoader, classpath: Seq[File], fork: ForkOptions, log: Logger): Task[TestOutput]  = {
+	def apply(runners: Map[TestFramework, Runner],  tests: List[TestDefinition], config: Execution, classpath: Seq[File], fork: ForkOptions, log: Logger): Task[TestOutput]  = {
 		val opts = config.options.toList
 		val listeners = opts flatMap {
 			case Listeners(ls) => ls
@@ -46,7 +46,7 @@ private[sbt] object ForkTests {
 							os.writeBoolean(log.ansiCodesSupported)
 							
 							val testsFiltered = tests.filter(test => filters.forall(_(test.name))).map{
-								t => new TaskDef(t.name, t.fingerprint, t.explicitlySpecified, t.selectors)
+								t => new TaskDef(t.name, forkFingerprint(t.fingerprint), t.explicitlySpecified, t.selectors)
 							}.toArray
 							os.writeObject(testsFiltered)
 
@@ -92,6 +92,12 @@ private[sbt] object ForkTests {
 				TestOutput(TestResult.Passed, Map.empty[String, SuiteResult], Iterable.empty)
 		} tagw (config.tags: _*)
 	}
+	private[this] def forkFingerprint(f: Fingerprint): Fingerprint with Serializable =
+		f match {
+			case s: SubclassFingerprint => new ForkMain.SubclassFingerscan(s)
+			case a: AnnotatedFingerprint => new ForkMain.AnnotatedFingerscan(a)
+			case _ => error("Unknown fingerprint type: " + f.getClass)
+		}
 }
 private final class React(is: ObjectInputStream, os: ObjectOutputStream, log: Logger, listeners: Seq[TestReportListener], results: mutable.Map[String, SuiteResult])
 {
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 23165f939..6d758f09a 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -484,7 +484,7 @@ object Defaults extends BuildCommon
 			case Tests.Group(name, tests, runPolicy) =>
 				runPolicy match {
 					case Tests.SubProcess(opts) =>
-						ForkTests(runners, tests.toList, config, loader, cp.files, opts, s.log) tag Tags.ForkedTestGroup
+						ForkTests(runners, tests.toList, config, cp.files, opts, s.log) tag Tags.ForkedTestGroup
 					case Tests.InProcess =>
 						Tests(frameworks, loader, runners, tests, config, s.log)
 				}
diff --git a/testing/agent/src/main/java/sbt/ForkMain.java b/testing/agent/src/main/java/sbt/ForkMain.java
index 5e70bb5ae..5ba0bba33 100755
--- a/testing/agent/src/main/java/sbt/ForkMain.java
+++ b/testing/agent/src/main/java/sbt/ForkMain.java
@@ -147,7 +147,7 @@ public class ForkMain {
 					public void warn(String s) { write(os, new Object[]{ForkTags.Warn, s}); }
 					public void info(String s) { write(os, new Object[]{ForkTags.Info, s}); }
 					public void debug(String s) { write(os, new Object[]{ForkTags.Debug, s}); }
-					public void trace(Throwable t) { write(os, t); }
+					public void trace(Throwable t) { write(os, new ForkError(t)); }
 				}
 			};
 
@@ -254,7 +254,7 @@ public class ForkMain {
 			} catch (Throwable t) {
 				try {
 					logError(os, "Uncaught exception when running tests: " + t.toString());
-					write(os, t);
+					write(os, new ForkError(t));
 				} catch (Throwable t2) {
 					internalError(t2);
 				}
@@ -263,7 +263,7 @@ public class ForkMain {
 		void internalError(Throwable t) {
 			System.err.println("Internal error when running tests: " + t.toString());
 		}
-		ForkEvent testEvent(final String fullyQualifiedName, final Fingerprint fingerprint, final Selector selector, final Status r, final Throwable err, final long duration) {
+		ForkEvent testEvent(final String fullyQualifiedName, final Fingerprint fingerprint, final Selector selector, final Status r, final ForkError err, final long duration) {
 			final OptionalThrowable throwable;
 			if (err == null)
 				throwable = new OptionalThrowable();
@@ -288,8 +288,9 @@ public class ForkMain {
 		}
 		ForkEvent testError(ObjectOutputStream os, TaskDef taskDef, String message, Throwable t) {
 			logError(os, message);
-			write(os, t);
-			return testEvent(taskDef.fullyQualifiedName(), taskDef.fingerprint(), new SuiteSelector(), Status.Error, t, 0);
+         ForkError fe = new ForkError(t);
+			write(os, fe);
+			return testEvent(taskDef.fullyQualifiedName(), taskDef.fingerprint(), new SuiteSelector(), Status.Error, fe, 0);
 		}
 	}
 }
diff --git a/testing/agent/src/main/java/sbt/FrameworkWrapper.java b/testing/agent/src/main/java/sbt/FrameworkWrapper.java
index 954e20f71..e7b75eaa0 100644
--- a/testing/agent/src/main/java/sbt/FrameworkWrapper.java
+++ b/testing/agent/src/main/java/sbt/FrameworkWrapper.java
@@ -1,6 +1,7 @@
 package sbt;
 
 import sbt.testing.*;
+import java.io.Serializable;
 
 final class FrameworkWrapper implements Framework {