cannot use import sources when using a dataset live connection (i.e. composite model)

[cnederveen]

I am trying to use a composite model in Power BI Desktop with a live connection to a  dataset in the PowerBI service. This will not work. If I am trying to connect I get: "The connect live option for this file is disabled because it already contains data from another data source. You cannot explore live data and connect to another type of datasource in the same file. Creat a new file to explore live data."  If I create a new file and connect to the dataset all the options in the external data section of the bar are greyed out. I fully expected this to work.  Why is this? What can I do about it? 

[v-qiuyu-msft]

Hi @cnederveen, 

This is a limitation currently, see: 

Since this connection is a live connection, left-navigation and modeling are disabled. You can only connect to one dataset in each report. This behavior is similar to the behavior when connected to SQL Server Analysis Services.

Please vote on this similar idea: https://ideas.powerbi.com/forums/265200-power-bi-ideas/suggestions/9908502-combine-live-data-with-im...

Best Regards,
Qiuyun Yu

[CarlosAndres]

Having the same issue.

I have a user inputting data in an Excel which was loaded to PBI service. From service, a live connection was established with PBI desktop, and the vreport created in desktop was published to service. Updates to the Excel are reflected all around, which is great. But in the PBI desktop file, if there is a live connection I  can't model, or even enter data from within the application. As OP noted, the options for modeling get grayed out.

The only other option I've found that works is to create the model in desktop, publish to service, and then establish a gateway connection between the dataset (now) in service and the Excel file. Not only cumbersome, but adds another layer of potential problems for mainitaing a live connection?

This is terrible implementation. If I understand correctly, Microsoft views as a risk that outside data will be implemented into the model. But couldn't you just do that in Excel and reimport into service? What's the difference? This because a workaround would be to create the model in Excel and import to PBI service, and Excel also uses Power Query!

Please help me make sense of all of this.

Thank you.