diff --git a/src/project_x_py/trading_suite.py b/src/project_x_py/trading_suite.py
index f1bf151..6be1f1e 100644
--- a/src/project_x_py/trading_suite.py
+++ b/src/project_x_py/trading_suite.py
@@ -982,6 +982,15 @@ async def disconnect(self) -> None:
         """
         logger.info("Disconnecting TradingSuite...")
 
+        # Disconnect realtime FIRST so the SignalR background reader thread is
+        # quiesced before any Polars data frames it writes into are freed. The
+        # previous order (cleanup contexts -> disconnect realtime) freed the
+        # frames while the reader was still live, racing native SignalR threads
+        # against Polars memory and corrupting the heap on disconnect
+        # (Windows STATUS_HEAP_CORRUPTION / 0xc0000374). See issue #98.
+        if self.realtime:
+            await self.realtime.disconnect()
+
         if self._instruments:
             # Multi-instrument mode - disconnect all contexts
             await self._disconnect_instrument_contexts()
@@ -989,10 +998,6 @@ async def disconnect(self) -> None:
             # Legacy single-instrument mode
             await self._disconnect_legacy_single_instrument()
 
-        # Disconnect realtime
-        if self.realtime:
-            await self.realtime.disconnect()
-
         # Clean up client context
         if hasattr(self, "_client_context") and self._client_context:
             try: