pivot table, loses grouping of dates on refresh

[philnotfil]

Pivot table grouping daily data into weekly data.

Worked on last week's report.

This week when I refreshed it, it lost the grouping that made it a weekly report. When I tried regrouping it, I didn't get the box that lets you decide how to group, it just made the selection a single group. To check the data from this last week (an entry with something that looked like a date, but wasn't really a date has caused this in the past) I set up another pivot table using only this week's data. It worked just fine.

Now what do I do?

 

[philnotfil]

I tried deleting this past week of data from and then refreshing the pivot table. The problem still occurred. Which is really bizarre, since it worked last week with that data set. Just for grins I tried deleting the last month of data and refreshing the pivot table, and the problem still occurred.

So it isn't a problem with the data that was entered? I've changed some kind of setting on the pivot table?

 

[philnotfil]

I pulled out the archive of last week's file, which did work lsat week, and it no longer works. Have I changed some sort of setting in Excel? Under PivotTable Options, Preserve cell formatting on update is selected. Is there another setting somewhere that would change this?