Problems replacing datasets

Hi,

I might be barking up the wrong tree, but here are some thoughts based on my own (albeit limited) experiences:

1) Are you trying to upload a dataset that has the SAME NAME, but you have changed something in the original dataset? If the answer to this is yes, make sure you save changes on BOTH the Excel side and the Power Pivot side. I have found that there are times when I have made changes to tables in Excel, but DID NOT go over to the Power Pivot side and save there as well. When I tried to refresh to Power BI, it didn't see the changes. Also--you need to make sure you refresh the tables in the Power Pivot data model as well. 

2) I have noticed that when I am saving my changes to a Sharepoint site (I am using a O365 Sharepoint), there is sometimes a delay in that save process. Look in the bottom right hand side of your screen to make sure it is showing that it is saving to your designated location. 

3) I believe that the NAME of the original file is critical. I don't change the name of my dataset because the connection between Power BI desktop and Excel will NOT pick up the changes in the file with the new name. 

I am sure that others, with more experience, may be able to add more/different comments that will be helpful to you. Meanwhile, I hope this helps.