diff --git a/Cargo.lock b/Cargo.lock
index 78dda3bb1..0b1341c7d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -329,6 +329,7 @@ dependencies = [
  "hdrhistogram",
  "humantime",
  "parking_lot",
+ "prost",
  "prost-types",
  "serde",
  "serde_json",
diff --git a/console-subscriber/Cargo.toml b/console-subscriber/Cargo.toml
index 113a4ceb3..7bdf8c8ef 100644
--- a/console-subscriber/Cargo.toml
+++ b/console-subscriber/Cargo.toml
@@ -46,6 +46,7 @@ hdrhistogram = { version = "7.3.0", default-features = false, features = ["seria
 # feature to also enable `tracing-subscriber`'s parking_lot feature flag.
 parking_lot_crate = { package = "parking_lot", version = "0.12", optional = true }
 humantime = "2.1.0"
+prost = "0.12"
 prost-types = "0.12.0"
 
 # Required for recording:
diff --git a/console-subscriber/src/aggregator/mod.rs b/console-subscriber/src/aggregator/mod.rs
index e3a1eb62a..b6846d62e 100644
--- a/console-subscriber/src/aggregator/mod.rs
+++ b/console-subscriber/src/aggregator/mod.rs
@@ -7,6 +7,7 @@ use std::{
 };
 
 use console_api as proto;
+use prost::Message;
 use proto::resources::resource;
 use tokio::sync::{mpsc, Notify};
 use tracing_core::{span::Id, Metadata};
@@ -22,6 +23,9 @@ mod shrink;
 use self::id_data::{IdData, Include};
 use self::shrink::{ShrinkMap, ShrinkVec};
 
+/// Should match tonic's (private) codec::DEFAULT_MAX_RECV_MESSAGE_SIZE
+const MAX_MESSAGE_SIZE: usize = 4 * 1024 * 1024;
+
 /// Aggregates instrumentation traces and prepares state for the instrument
 /// server.
 ///
@@ -278,26 +282,57 @@ impl Aggregator {
     /// Add the task subscription to the watchers after sending the first update
     fn add_instrument_subscription(&mut self, subscription: Watch<proto::instrument::Update>) {
         tracing::debug!("new instrument subscription");
-
-        let task_update = Some(self.task_update(Include::All));
-        let resource_update = Some(self.resource_update(Include::All));
-        let async_op_update = Some(self.async_op_update(Include::All));
         let now = Instant::now();
 
-        let update = &proto::instrument::Update {
-            task_update,
-            resource_update,
-            async_op_update,
-            now: Some(self.base_time.to_timestamp(now)),
-            new_metadata: Some(proto::RegisterMetadata {
-                metadata: (*self.all_metadata).clone(),
-            }),
+        let update = loop {
+            let update = proto::instrument::Update {
+                task_update: Some(self.task_update(Include::All)),
+                resource_update: Some(self.resource_update(Include::All)),
+                async_op_update: Some(self.async_op_update(Include::All)),
+                now: Some(self.base_time.to_timestamp(now)),
+                new_metadata: Some(proto::RegisterMetadata {
+                    metadata: (*self.all_metadata).clone(),
+                }),
+            };
+            let message_size = update.encoded_len();
+            if message_size < MAX_MESSAGE_SIZE {
+                // normal case
+                break Some(update);
+            }
+            // If the grpc message is bigger than tokio-console will accept, throw away the oldest
+            // inactive data and try again
+            self.retention /= 2;
+            self.cleanup_closed();
+            tracing::debug!(
+                retention = ?self.retention,
+                message_size,
+                max_message_size = MAX_MESSAGE_SIZE,
+                "Message too big, reduced retention",
+            );
+
+            if self.retention <= self.publish_interval {
+                self.retention = self.publish_interval;
+                break None;
+            }
         };
 
-        // Send the initial state --- if this fails, the subscription is already dead
-        if subscription.update(update) {
-            self.watchers.push(subscription)
+        match update {
+            // Send the initial state
+            Some(update) => {
+                if !subscription.update(&update) {
+                    // If sending the initial update fails, the subscription is already dead,
+                    // so don't add it to `watchers`.
+                    return;
+                }
+            }
+            // User will only get updates.
+            None => tracing::error!(
+                min_retention = ?self.publish_interval,
+                "Message too big. Start with smaller retention.",
+            ),
         }
+
+        self.watchers.push(subscription);
     }
 
     fn task_update(&mut self, include: Include) -> proto::tasks::TaskUpdate {