The datatype of column '<1s>' in the '<0s>' table can't be changed because it participates in index '<2s>'.

Microsoft Office Access 2003

The datatype of column '<1s>' in the '<0s>' table can't be changed because it participates in index '<2s>'.

The sum of the lengths of all columns in an index can not exceed 256 bytes. Changing to the specified datatype would exceed the maximum index size of <3d> bytes.

For more information, see About Database Designer Considerations for SQL Server Databases and Create an Index.