diff --git a/src/runtime/block.rs b/src/runtime/block.rs
index 1b548b01..7ddfc345 100644
--- a/src/runtime/block.rs
+++ b/src/runtime/block.rs
@@ -214,7 +214,7 @@ impl<T: Kernel + Send + 'static> TypedBlock<T> {
         }
         let h = mio.input(id).get_handler();
         let f = (h)(kernel, io, mio, meta, p);
-        f.await.or(Err(Error::HandlerError))
+        f.await.map_err(|e| Error::HandlerError(e.to_string()))
     }
 
     async fn run_impl(
@@ -326,12 +326,12 @@ impl<T: Kernel + Send + 'static> TypedBlock<T> {
                                     meta.instance_name().unwrap(),
                                 );
                             }
-                            Err(Error::HandlerError) => {
+                            Err(e @ Error::HandlerError(..)) => {
                                 error!(
-                                    "{}: BlockMessage::Call -> HandlerError. Terminating.",
+                                    "{}: BlockMessage::Call -> {e}. Terminating.",
                                     meta.instance_name().unwrap(),
                                 );
-                                return Err(Error::HandlerError);
+                                return Err(e);
                             }
                             _ => {}
                         }
@@ -347,16 +347,16 @@ impl<T: Kernel + Send + 'static> TypedBlock<T> {
                         )
                         .await
                         {
-                            Err(Error::HandlerError) => {
+                            Err(e @ Error::HandlerError(..)) => {
                                 error!(
-                                    "{}: Error in callback. Terminating.",
+                                    "{}: BlockMessage::Callback -> {e}. Terminating.",
                                     meta.instance_name().unwrap(),
                                 );
                                 let _ = tx.send(Err(Error::InvalidMessagePort(
                                     BlockPortCtx::Id(block_id),
                                     port_id,
                                 )));
-                                return Err(Error::HandlerError);
+                                return Err(e);
                             }
                             res => {
                                 let _ = tx.send(res);
diff --git a/src/runtime/flowgraph.rs b/src/runtime/flowgraph.rs
index a60f7432..ff0ecf61 100644
--- a/src/runtime/flowgraph.rs
+++ b/src/runtime/flowgraph.rs
@@ -157,7 +157,7 @@ impl FlowgraphHandle {
             })
             .await
             .or(Err(Error::InvalidBlock(block_id)))?;
-        rx.await.or(Err(Error::HandlerError))?
+        rx.await?
     }
 
     /// Call message handler
@@ -177,7 +177,7 @@ impl FlowgraphHandle {
             })
             .await
             .map_err(|_| Error::InvalidBlock(block_id))?;
-        rx.await.map_err(|_| Error::HandlerError)?
+        rx.await?
     }
 
     /// Get [`FlowgraphDescription`]
diff --git a/src/runtime/mocker.rs b/src/runtime/mocker.rs
index b43a0952..151d9c41 100644
--- a/src/runtime/mocker.rs
+++ b/src/runtime/mocker.rs
@@ -113,7 +113,7 @@ impl<K: Kernel + 'static> Mocker<K> {
         } = &mut self.block;
         let h = mio.input(id).get_handler();
         let f = (h)(kernel, &mut io, mio, meta, p);
-        async_io::block_on(f).or(Err(Error::HandlerError))
+        async_io::block_on(f).map_err(|e| Error::HandlerError(e.to_string()))
     }
 
     /// Get data from output buffer
diff --git a/src/runtime/mod.rs b/src/runtime/mod.rs
index cff41d94..f1a75d9f 100644
--- a/src/runtime/mod.rs
+++ b/src/runtime/mod.rs
@@ -237,8 +237,8 @@ pub enum Error {
     #[error("Connect error: {0}")]
     ConnectError(Box<ConnectCtx>),
     /// Error in handler
-    #[error("Error in handler")]
-    HandlerError,
+    #[error("Error in message handler: {0}")]
+    HandlerError(String),
     /// Block is already terminated
     #[error("Block already terminated")]
     BlockTerminated,
@@ -260,6 +260,9 @@ pub enum Error {
     /// Duplicate block name
     #[error("A Block with an instance name of '{0}' already exists")]
     DuplicateBlockName(String),
+    /// Error returned from a Receiver when the corresponding Sender is dropped
+    #[error(transparent)]
+    ChannelCanceled(#[from] oneshot::Canceled),
 }
 
 #[cfg(feature = "seify")]
diff --git a/src/runtime/runtime.rs b/src/runtime/runtime.rs
index b943ae48..581f7728 100644
--- a/src/runtime/runtime.rs
+++ b/src/runtime/runtime.rs
@@ -534,9 +534,9 @@ pub(crate) async fn run_flowgraph<S: Scheduler>(
                         .await
                         .is_ok()
                     {
-                        match block_rx.await {
-                            Ok(Ok(p)) => tx.send(Ok(p)).ok(),
-                            _ => tx.send(Err(Error::HandlerError)).ok(),
+                        match block_rx.await? {
+                            Ok(p) => tx.send(Ok(p)).ok(),
+                            Err(e) => tx.send(Err(Error::HandlerError(e.to_string()))).ok(),
                         };
                     } else {
                         let _ = tx.send(Err(Error::BlockTerminated));