diff --git a/src/sql/workbench/api/common/extHostNotebook.ts b/src/sql/workbench/api/common/extHostNotebook.ts
index 5bd34380c9..58641942a2 100644
--- a/src/sql/workbench/api/common/extHostNotebook.ts
+++ b/src/sql/workbench/api/common/extHostNotebook.ts
@@ -108,7 +108,7 @@ export class ExtHostNotebook implements ExtHostNotebookShape {
 				};
 				return details;
 			} catch (error) {
-				throw typeof (error) === 'string' ? new Error(error) : error;
+				throw typeof (error) === 'string' ? new Error(error) : Object.assign(error, { errorCode: error.response?.status }); // Add errorCode so that status info persists over RPC
 			}
 		});
 	}
diff --git a/src/sql/workbench/services/notebook/browser/models/clientSession.ts b/src/sql/workbench/services/notebook/browser/models/clientSession.ts
index 6ddc9986af..ced8cfd585 100644
--- a/src/sql/workbench/services/notebook/browser/models/clientSession.ts
+++ b/src/sql/workbench/services/notebook/browser/models/clientSession.ts
@@ -50,6 +50,8 @@ export class ClientSession implements IClientSession {
 	private _kernelConfigActions: ((kernelName: string) => Promise<any>)[] = [];
 	private _connectionId: string = '';
 
+	private readonly _kernelNotFoundError = 501;
+
 	constructor(private options: IClientSessionOptions) {
 		this._notebookUri = options.notebookUri;
 		this._executeManager = options.executeManager;
@@ -62,7 +64,6 @@ export class ClientSession implements IClientSession {
 	public async initialize(): Promise<void> {
 		try {
 			this._serverLoadFinished = this.startServer(this.options.kernelSpec);
-			await this._serverLoadFinished;
 			await this.initializeSession();
 			await this.updateCachedKernelSpec();
 		} catch (err) {
@@ -116,8 +117,8 @@ export class ClientSession implements IClientSession {
 			session.defaultKernelLoaded = true;
 		} catch (err) {
 			// TODO move registration
-			if (err && err.response && err.response.status === 501) {
-				this.options.notificationService.warn(localize('kernelRequiresConnection', "Kernel {0} was not found. The default kernel will be used instead.", kernelSpec.name));
+			if (err.response?.status === this._kernelNotFoundError || err.errorCode === this._kernelNotFoundError) {
+				this.options.notificationService.warn(localize('kernelRequiresConnection', "Kernel '{0}' was not found. The default kernel will be used instead.", kernelSpec.name));
 				session = await this._executeManager.sessionManager.startNew({
 					path: this.notebookUri.fsPath,
 					kernelName: undefined
diff --git a/src/vs/base/common/errors.ts b/src/vs/base/common/errors.ts
index fee554bb1d..4639e688dd 100644
--- a/src/vs/base/common/errors.ts
+++ b/src/vs/base/common/errors.ts
@@ -104,12 +104,14 @@ export function transformErrorForSerialization(error: any): any;
 export function transformErrorForSerialization(error: any): any {
 	if (error instanceof Error) {
 		let { name, message } = error;
+		let errorCode = (<any>error).errorCode; // {{SQL CARBON EDIT}} Add error code to retain more information
 		const stack: string = (<any>error).stacktrace || (<any>error).stack;
 		return {
 			$isError: true,
 			name,
 			message,
-			stack
+			stack,
+			errorCode
 		};
 	}
 
diff --git a/src/vs/workbench/services/extensions/common/rpcProtocol.ts b/src/vs/workbench/services/extensions/common/rpcProtocol.ts
index 5f97fcd13a..7273143a26 100644
--- a/src/vs/workbench/services/extensions/common/rpcProtocol.ts
+++ b/src/vs/workbench/services/extensions/common/rpcProtocol.ts
@@ -445,6 +445,7 @@ export class RPCProtocol extends Disposable implements IRPCProtocol {
 				err.name = value.name;
 				err.message = value.message;
 				err.stack = value.stack;
+				err.errorCode = value.errorCode; // {{SQL CARBON EDIT}} Include custom error code
 			} else {
 				err = value;
 			}