A Microsoft file hosting and synchronization service.
Hello, thank you for reaching out to Microsoft Q&A.
May I please know if your hard disk storage is full?
OneDrive desktop app creates a OneDrive local folder on your device. This local folder just syncs to the Cloud. (Local disk C:/ Users/ Your_Username/OneDrive)
So when you copy the files to OneDrive, Windows first writes them to the OneDrive local folder and then syncs/upload your files to the cloud. So, if your disk is low on Storage, you may receive this error.
Try OneDrive online -
Open an incognito tab on any web browser and sign in with your Microsoft account here.
Click +Create or Upload.
Select Folder upload.
Select the folder by batches and then complete the backup.