Error on Distinct

[daryllabar]

Trying to run this query:

SELECT DISTINCT [From] FROM email 

Getting this error

Msg 10337, Level 16, State 1, Line 9
An unexpected error occurred.

System.ArgumentNullException: Key cannot be null.
Parameter name: key
See the Execution Plan tab for details of where this error occurred

[MarkMpn]

Interesting - can you please try this as a workaround for now?

SELECT DISTINCT [From] + '' FROM email 

[daryllabar]

That appears to work.