---
title: "Enabling CLR Integration"
description: Microsoft SQL Server hosting CLR is called CLR integration, which is disabled by default. Use the sp_configure stored procedure to enable CLR integration.
author: rwestMSFT
ms.author: randolphwest
ms.date: 12/27/2024
ms.service: sql
ms.subservice: clr
ms.topic: "reference"
helpviewer_keywords:
  - "clr enabled option"
  - "common language runtime [SQL Server], enabling"
---
# Enable CLR integration

[!INCLUDE [SQL Server SQL MI](../../includes/applies-to-version/sql-asdbmi.md)]

The common language runtime (CLR) integration feature is off by default. To use objects that are implemented using CLR integration, use the [clr enabled](../../database-engine/configure-windows/clr-enabled-server-configuration-option.md) server configuration option in [!INCLUDE [ssManStudioFull](../../includes/ssmanstudiofull-md.md)] to enable CLR integration:

```sql
EXECUTE sp_configure 'clr enabled', 1;
RECONFIGURE;
GO
```

You can disable CLR integration by setting the `clr enabled` option to 0. When you disable CLR integration, [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] stops executing all user-defined CLR routines and unloads all application domains. Features that rely upon the CLR, such as the **hierarchyid** data type, the `FORMAT` function, replication, and Policy-Based Management, aren't affected by this setting and continue to function.

> [!NOTE]  
> Though the `clr enabled` configuration option is enabled in [!INCLUDE [ssazure-sqldb](../../includes/ssazure-sqldb.md)], developing CLR user functions aren't supported in [!INCLUDE [ssazure-sqldb](../../includes/ssazure-sqldb.md)].

## Permissions

To enable CLR integration, you must have `ALTER SETTINGS` server level permission, which is implicitly held by members of the **sysadmin** and **serveradmin** fixed server roles.

## Remarks

Computers configured with large amounts of memory and a large number of processors might fail to load the CLR integration feature of SQL Server when starting the server. To address this issue, start the server by using the `-gmemory_to_reserve` [!INCLUDE [ssNoVersion](../../includes/ssnoversion-md.md)] service startup option, and specify a memory value large enough. For more information, see [Database Engine Service startup options](../../database-engine/configure-windows/database-engine-service-startup-options.md).

> [!NOTE]  
> Common language runtime (CLR) execution isn't supported under lightweight pooling. Before enabling CLR integration, you must disable lightweight pooling. For more information, see [Server configuration: lightweight pooling](../../database-engine/configure-windows/lightweight-pooling-server-configuration-option.md).

## Related content

- [sp_configure (Transact-SQL)](../system-stored-procedures/sp-configure-transact-sql.md)
- [clr enabled Server Configuration Option](../../database-engine/configure-windows/clr-enabled-server-configuration-option.md)
- [RECONFIGURE (Transact-SQL)](../../t-sql/language-elements/reconfigure-transact-sql.md)
- [GRANT (Transact-SQL)](../../t-sql/statements/grant-transact-sql.md)
- [Server-level roles](../security/authentication-access/server-level-roles.md)