ArcGIS Pro 3.1 "Export layout failed."

[PeterBrownParkCO]

After upgrading to ArcGIS Pro 3.1, I am unable to export layouts in any format while in the project I had open during the update to 3.1. I click the export button and within 3 seconds, I get an "Export layout failed" message. 

I even tried to export a blank layout with nothing added to it yet and get the same message.

I am able to save as a layout file and open that layout file in a different, existing project and it exports from any of those other projects just fine.

Any ideas would be appreciated. Thanks for your help.

[DenisLalonde]

Google led me to this old thread. I upgraded to V3.4 last week and am now seeing the "Export Failed" when exporting some layouts to PDF (some mysteriously export correctly however). Went through most of the fixes including making sure no layers were old "Selection Layers" carried over from Importing an MDX - but the issue persists.

Wondering if others have seen this old bug resurface?