sql - IDENTITY INSERT not working with MERGE -

i have following code:

print n'merging wide format types...' set identity_insert wideformattypes on go merge wideformattypes target using (values      (1, n'****', null),     (2, n'****', null),     (3, n'******', null),     (4, n'*******', null),     (5, n'******', null),     (6, n'*******', null) ) source (typeid, typename, description)  on target.typeid = source.typeid when matched     update set     typeid = source.typeid,     typename = source.typename,     description = source.description when not matched target      insert (typeid, typename, description)      values (typeid, typename, description);  set identity_insert wideformattypes off go 

it returns error

msg 8102, level 16, state 1, line 1
cannot update identity column 'typeid'

the table declared follows:

create table [dbo].[wideformattypes]  (     [typeid]      int             identity (1, 1) not null,     [typename]    nvarchar (500)  not null,     [description] nvarchar (1000) null,     primary key clustered ([typeid] asc) ); 

i can't find problem.. ?

try removing identity column update portion of merge.

identity_insert is, says, inserts, not updates. also, include field in join update never change value anyway.