HI @Paul Tovar
According to your case description, when accessing a document library in SharePoint, you want to add a new column to a folder, but an error occurs: "To update this folder, go to the channel in Microsoft Teams."
After my test, new columns can be added normally. Please make sure you have permission to edit the file library. If not, please contact your SharePoint administrator.
My test steps:
Add a SharePoint document library in Teams: Open Teams and select a channel. Click the "+" sign to the right of the channel name and select "SharePoint". Select the document library and add it as a tab.
Manage a document library in Teams: Make sure to make changes in the document library tab in Teams. After opening the document library tab in Teams, you should be able to add new columns and make other changes. Or open it in SharePoint and modify the view there.
If you still encounter an error, try accessing the document library through the Teams web client to see if this solves the problem.
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