Hi Dan Thanks for your steer. I think it is a bug in OneDrive. Following your suggestion I tried to convert a CSV file to a table in my project geodatabase using Conversion Tools\Table to Geodatabase. Again Arc could not "see" the CSV file that is sitting on my C Drive at C:\Users\[my_username]\OneDrive\Documents\etc. This is the local drive directory that OneDrive syncs to its cloud server. My entire ArcGIS Pro project is in this directory, including the project Geodatabase. When I copied all the CSV files out to my standard Documents directory, I was able to convert the data to tables in my project geodatabase (which itself is still in the local OneDrive directory). I could also salvage all the symbology and labeling formatting. So all good now with that work-around but there is definitely a bug/issue with Arc recognizing csv and excel files that are syncing with OneDrive. Thanks again
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