Enabling CLR allows the creation of CLR functions, stored procedures, triggers, user-defined aggregates and user-defined types.

• This is Disabled by default. Enable only if fully justified.
• If enabled, Permission should be set to SAFE_ACCESS (not EXTERNAL_ACCESS or UNSAFE)
• If enabled, the default Permission is SAFE. Change this Permission only if fully justified.

Check

SELECT name, 

      CAST(value as int) as value_configured, 

      CAST(value_in_use as int) as value_in_use 

FROM sys.configurations 

WHERE name = 'clr enabled';

Both value columns will show 0 if CLR is disabled.

To check if CLR assemblies are in use...

USE [<database_name>]

GO 

SELECT name AS Assembly_Name, permission_set_desc 

FROM sys.assemblies 

WHERE is_user_defined = 1; 

GO

To check if Permission is set to SAFE_ACCESS...

SELECT name, 

       permission_set_desc 

FROM sys.assemblies 

WHERE is_user_defined = 1;

To set assemblies to SAFE use this code:

ALTER ASSEMBLY WITH PERMISSION_SET = SAFE; 

Be aware that an alternate value is likely to have been set purposefully, so this change carries a risk that the assembly may cease to function as intended.

Disable

EXECUTE sp_configure 'clr enabled', 0; 

RECONFIGURE;

Bibliography