A Microsoft file hosting and synchronization service.
Hi
JanHS1999,
SharePoint online (including OneDrive fir business) has resource throttles and limits that govern the amount of data and throughput that can be managed. The List View Threshold is by default, approximately 5000 items.
When the defined item limit in a list/library is exceeded, the message “The attempted operation is prohibited because it exceeds the list view threshold enforced by the administrator” is displayed reminding you that the limit.
In this case, you must select the items in folder and delete them. I understand this is time consuming, since SharePoint online has a limit, you may have to repeat this action to be able to delete the folder.
We appreciate your understanding.
Regards,
Neha