I'd like to make sure I understand your workflow here.
You say that you're "sharing Power BI files online" - do you mean you're authoring something in PBI Desktop, then consuming it in the cloud, trying to publish a report to the web, or something else that I'm not thinking of? My next question is - does this happen in other browsers than IE?
If you're authoring something in Desktop and then it hangs like this when you try to open it in the cloud, that's not expected behavior. We would need to get more info about your specific dataset (or a representative sample) to troubleshoot it.