Is the 4.2 excel addin compatible with Hyperion SmartView 11.142.610?

In 4.2 you don't need an add-in and can do it all right in XF Spreadsheet, Desktop app. Since these add-ins (XF and Hyperion) don't share DLL's there should be no conflict. In prior versions of XF there was a login and sequence to authenticate both at the same time so an end user can be connected to both simultaneously.

So far I have found how happily the SmartView and OneStream addins can coexist depends on the version of Excel the client or the partner have.
Excel 2013 didn’t seem to have the issue that you need to disable SmartView before been able log into OneStream as is the case with Excel 2016.

I suspect it has something to do with the way Microsoft has changed how addins are able to reference memory in the newer releases.

At a customer we had a good spec VM setup with Smart View and OneStream addins with Excel 2016. Just need to disable Smart View and in both Addins and COM then restart Excel, login to OneStream just on a blank workbook then re-enable Smart View. Just be sure not to click on Smart View connection manager as that crashes Excel, so you need to set the connection and use the same connection name in the retrieve spreadsheet.