Hi @forresto ,
From the link you provided, it seems that he is using share folder to access the file such as \sharepoint\folder\file.xlsx.
I'm not familiar with SP, please have a check that you could also access the UNC path with SSIS and then you may load data to the excel on Sharepoint.
If this do not work, please consider downloading the excel file from SP first and then re-write and upload to SP.
This could also be done from SSIS.
https://www.techbrothersit.com/2016/07/how-to-download-file-from-sharepoint-by.html
Regards,
Zoe Hui
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