Excel 2007 Pivot Table - Can't Group On Dates

[Steve1944]

I have a stripped down data source for debugging purposes
I only have 4 rows of data for test purposes. The dates are formatted as dates

When I create the pivot table the dates become my column values.
When I select the first date in the pivot table the Group By Field menu option is grayed out.
I tried setting a tabular format but didn't work.

 

[DataAnalyst]

Hi, I also had this problem. In case anyone else does, I want to share my experience.
I'm working with data that was pulled elsewhere and sent to me as an Excel 2013 file.
I couldn't group the dates - I've noticed this before but hadn't taken the time to address it.
I changed the format to date, used text to columns, deleted and re-created the pivot several times, used Ctrl-Shft-arrow to check for blanks in the data and found none.
I also saved, closed and re-opened the file after deleting the pivot and then re-created it. None of this helped, it still wouldn't group.
On another site I saw to use filter in the data and look at the pulldown in the date field - If it's date it will group into years and months.
I did this and saw years months, and "Nulls".
It turns out there were several rows with the value "Null" in the date field. They weren't discovered by using Ctrl-Shft-arrow to check for blanks - they're not blank...
These are corrections entered by corporate around the end of the year - not real entries. I changed all these to 12/31/16 by using the filter and copying to "select visible cells only"
Deleted the pivot again and re-created it and now it groups! Yay! :D
Hope this helps!