diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/TraceRunnable.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/TraceRunnable.java
index cbf838713..688269354 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/TraceRunnable.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/TraceRunnable.java
@@ -74,6 +74,10 @@ public class TraceRunnable implements Runnable {
 	}
 
 	protected void close(Span span) {
+		// race conditions - check #447
+		if (!this.tracer.isTracing()) {
+			this.tracer.continueSpan(span);
+		}
 		this.tracer.close(span);
 	}
 
@@ -82,7 +86,10 @@ public class TraceRunnable implements Runnable {
 	}
 
 	protected Span detachSpan(Span span) {
-		return this.tracer.detach(span);
+		if (this.tracer.isTracing()) {
+			return this.tracer.detach(span);
+		}
+		return span;
 	}
 
 	public Tracer getTracer() {
diff --git a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptor.java b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptor.java
index e61ef7b5b..9da6a0cc2 100644
--- a/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptor.java
+++ b/spring-cloud-sleuth-core/src/main/java/org/springframework/cloud/sleuth/instrument/messaging/TraceChannelInterceptor.java
@@ -116,7 +116,10 @@ public class TraceChannelInterceptor extends AbstractTraceChannelInterceptor {
 			spanFromHeader.logEvent(Span.SERVER_SEND);
 			addErrorTag(ex);
 		}
-		getTracer().detach(spanFromHeader);
+		// related to #447
+		if (getTracer().isTracing()) {
+			getTracer().detach(spanFromHeader);
+		}
 	}
 
 	private void addErrorTag(Exception ex) {