is of a type that is invalid for use as a key column in an index

Question

I have an error at

Column \'key\' in table \'misc_info\' is of a type that is invalid for use as a key column in an index.

where key is a n

Answer 1

The only solution is to use less data in your Unique Index. Your key can be NVARCHAR(450) at most.

"SQL Server retains the 900-byte limit for the maximum total size of all index key columns."

Read more at MSDN