Sum not updating when new data input

=SUM() not updating when new data is input. This happened with vers (4) and is repeated with 5.0.4.2 .
Also,c the =SUM formula will not copy.
Why is the process for asking a question so complicated. What is a tag?

A tag is essentially a keyword used to characterize the question so that it, and related ones, can be found more readily in the future. For example clicking the tag “calc” on this question will give all the questions that have that tag.

Do you have AutoCalculate (Tools/Cell contents) turned off?

I recently upgraded to 5.0.4.2 and my =SUM() seems to be working just fine. I just tested; I can add new data and I can copy the =SUM formula.

Please supply a sample we can review to help find the problem.