Reference isn't Valid Error on opening a Workbook

[debkat]

Hi Guys,

I have been developing a very heavy workbook for a client, and it is looking good and everything is working as expected. However, when I open the file, I am getting the "Reference isn't Valid" alert.

I have checked Name Manager ... there are not missing references.
I have deleted and recreated all slicers.
There is no debugger option at that point.
I have checked Developer > Tools > References ... there is nothing that appears broken.

Any other ideas of things that I can check?

Thanks so much,
Deb

[TMS]

Have you checked for links to other files?

[debkat]

Thanks, but there are no links to other files in the workbook.

I'm still looking for suggestions.