"Operation Must Use an Updateable Query" Problem

[McArthurGDM]

I have two different Update Queries. Both Update Queries are structured in the same manner. Note in the pictures below that I am updating a Table called "ValueT". SHUSAAgg2 and ValueID are both queries that I want to update the table with.



However, one of the Update Queries works and the other gives me an error that says "Operation Must Use an Updateable Query".

NOTE: It's worth noting that SHUSAAgg2 uses an aggregate function, however, I took this query and threw it into another query that dosent use an aggregate function and it still gave me the error.

Why is this?

[JoeM]

Here is a good list of things to check: http://allenbrowne.com/ser-61.html