Error validating the default for column newsequentialid
With SQL Server 2008, FILESTREAM support was added to SQL Server.
File Stream allows creation of large objects as File System objects instead of database objects.
Since Merge Replication requires a rowguid column to be present on the table, we also added a new unique identifier column to the table, with a default constraint of NEWSEQUENTIALID().newsequentialid is primarily to solve the issue of page fragmentation when your table is clustered by a uniqueidentifier. I set up two test tables, one where the newsequentialid column is the primary key and one where it is not (like yours), and in the primary key the GUIDs were always sequential. I do not know the internals/technical reasons it behaves that way, but it seems clear that newsequentialid() is only truly sequential when your table is clustered by it.Otherwise, it seems to behave similarly to newid() / Row Guid.More details about the problem in my MSDN's blog at I added a brand new uniqueidentifier column to an existing table and set the default as newsequentialid().It succeeded without errors; however, when I reentered the design view and tried to set the column as a 'unique key' index, upon saving the table I got the message: "Error validating the default for column XYZ. ", exactly as described here: There is no reason why I shouldn't be able to call "select newsequentialid()" just as I can call "select newid()".