Cannot group selection

[srmorgan]

I am doing a simple pivot table. Twelve rows, two columns, The source is a large range on another tab with about 20,000 lines. My data is clean, I have run other pivot tables using this range in other files.
It will not allow me to group my rows giving me that "unable to group selection: message and I am stumped.
I could try to find last year's pivot for the same data (this is for an annual forecast) and change the source but why can't I group this data?

Any suggestions or ways around this would be welcome.

Thank you to all

 

[steve the fish]

Dates id imagine? Check they are all valid in your data.

 

[srmorgan]

Dates id imagine? Check they are all valid in your data.

Not dates, Actually insurance companies, and I have done these groupings before, it just doesn't seem to work with this particular data download

Thanks

 

[steve the fish]

There is something wrong with your data but difficult as i cant see it.

 

[srmorgan]

There is something wrong with your data but difficult as i cant see it.

This is confidential data and I can't do any uploading with it.
Thank you

 

[srmorgan]

This is confidential data and I can't do any uploading with it.
Thank you

Steve, I went back into decision support and re-ran and now I can group, I think, keep your fingers crossed