How to resolve datatype length difference errors while using unpivot in SQL Server?

I am running below SQL statements in SQL Server which is causing issues due to difference in length of the column types (name=nvarchar(100), address=nvarchar(250)).

select distinct  
    Id, Label, [Value]
from
    (select distinct 
         coalesce([Value], 'unknown') as Id,
         coalesce([Value], 'unknown') + ':' + I as label,
         coalesce([Value], 'unknown') as [Value]
     from 
         [dummyDB].[test].[test]
     unpivot
         ([Value] for I in (name, address)) as dataTable
    ) as t

Error:

Msg 8167, Level 16, State 1, Line 7
The type of column "address" conflicts with the type of other columns specified in the UNPIVOT list.

How to get this resolved?

If you use APPLY and VALUES to unpivot the data instead, you don't get this error. Using these tools is more versatile that the UNPIVOT operator anyway, so I personally prefer them:

SELECT T.ID,
       V.Label,
       V.[Value]
FROM dbo.Test T
     CROSS APPLY (VALUES('Name',T.Name),
                        ('Address',T.Address))V(Label,Value);

If you have non string-type columns, you'll need to explicitly convert them (possibly with a style code):

SELECT T.ID,
       V.Label,
       V.[Value]
FROM dbo.Test T
     CROSS APPLY (VALUES('Name',T.Name),
                        ('Address',T.Address),
                        ('SomeDate',CONVERT(nvarchar(10),T.SomeDate,112)),
                        ('SomeInt',CONVERT(nvarchar(5),T.SomeInt)))V(Label,Value);