Unable to group on date, no pop-up

[pbexcel]

Office 2007

I have a large sheet of info I wish to analyse by date1, date2, and Name.
I only want to include those rows of date1 which are from 01/04/2014 to 31/03/2014 (UK format)
I want to Group date2 by Month
And I want to do a Count of Name so it gives me the number of occurences in each Month of date2. Should be simple!

I have done this before for previous years of date1 but my current year analysis is not letting me group by Month.
When I try Group, the pop up does not appear, it just produces a sub heading of "+ Group" above the column and a second occurence of the date2 in the Row Labels box.

I guess it does not like the data structure but I cannot see what is different, it is driving me mad !!

[Richard Buttrey]

Difficult to be certain without seeing the workbook but usually a failure to group by a date column is because one of the cells in the date range in question is not a date number. Have you checked each date to see - use =ISNUMBER(A1) in a he;per column first to tocheck.

[pbexcel]

Thanks for the reply.
The sheets are a bit big to post, I will see if I can cut it down and anomonise (?) it.
Yes they are all dates ecxcept where there are blanks, ISNUMBER returns FALSE for both date columns.

[pbexcel]

I made a new ss with a cutdown copy of the worksheet, just the 3 required columns and remade the pivot table......and it worked ????
I am even more puzzled now!