Problem: When copying a file from SharePoint Online through file explorer, I got this error message:
“An unexpected error is keeping you from copying the folder. If you
continue to receive this error, you can use the error code to search for
help with this problem. Error 0x800700DF: The file size exceeds the limit allowed and cannot be saved.”
Also, when I tried opening the file directly, received “Could not open file <File-URL>. Probable cause: File Sharing or file permissions problem”.
I’ve seen this error in the SharePoint On-premises environment when the user tries to upload a file larger than the maximum limit configured in the Central Administration site (Central Administration >> Application Management >> Select Your Web App >> General Settings >> Maximum upload size).
Here in SharePoint Online, the root cause of this issue is the limit set on a Web client service responsible for opening files through file explorer (or mapped network drive!). By default, Larger files over 100 MB stored in SharePoint can’t be directly opened in the Mapped Drive/File Explorer view due to the file size limit of the web client service. Here is how to increase the file size download limit in the client machine:
- Open Windows Registry using “regedit” command as an administrator.
- Navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\WebClient\Parameters
- Right-click on the FileSizeLimitInBytes and click Modify
- Click on Decimal, type 500000000, and click OK (500 MB!)
- Go to Services snapin (services.msc) and Restart Web Client service. You may have to restart the machine at times.
This will increase the limit of the web client file size to 500 MB, which is the maximum file size you can download using WebDAV.
Microsoft KB article addressing this issue: https://support.microsoft.com/en-us/topic/folder-copy-error-message-when-downloading-a-file-that-is-larger-than-50000000-bytes-from-a-web-folder-815e2949-0f56-ec25-db7d-b6d860a31f77