Exception Details
Duplicate tag exists in file.
We encountered this error when trying to upload a .CSV file through the data management framework in Dynamics 365 for Finance and Operations.
The file was originally edited in Excel and saved in the comma separated value format. However, when the file is reopened in Excel, the data structure looks like. There are not visible duplicate tags.
Solution
Open the file with notepad or a basic text editor. Look if you see a string of extra columns at the end of each row. If so, then delete the extra commas by performing a Find Replace.
Save the file.
Reattempt upload.