DriveHQ's enterprise WebDAV Drive Mapping service allows you to map DriveHQ cloud storage as a network drive. You can map multiple drives to different folders, incl. shared folders.

If a user shared a folder to you with "Add / Upload" permission, and if you access the shared folder from your mapped drive, you will be able to see and download all files and subfolders in the shared folder. You can also upload files/folders into the shared folder, but you cannot delete files/folders or modify them in the shared folder. 

However, there was a problem: if a user creates a new file in the shared folder, Windows Explorer will name it as "New Document.EXT". Normally, you will rename it to a real file name. However, since you cannot modify the file, you will not be able to rename it. Moreover, the new file is 0 byte. You cannot add any data to the file. The same is true for folders. You can create a new folder with the default name "New Folder", but you cannot change it to a more meaningful name.

When you copy and paste files / folders into the shared folder, Windows Explorer may report the following error:

"An unexpected error is keeping you from copying the file. If you continue to receive this error, you can use the error code to search for help with this problem. Error 0x80070780: The file cannot be accessed by the system."

The reason is Windows Explorer takes two steps to copy a file: (1) Create an empty file with the same name; (2) Write data to the empty file. Since the share permission is Add / Upload, the second step will fail. The same problem does not happen with DriveHQ FileManager or browser.

Because of this problem, using a mapped drive with Add / Upload permission was not useful.

Our engineers have worked out a solution. They have tweaked the permission slightly:

(1) If a file or folder is empty, even if it is shared to you with Add / Upload permission, you can still rename, delete or edit it.

(2) If a file or folder was created within the last 45 seconds, even if it is shared to you with Add / Upload permission, you can still rename, delete or edit it.

With the above workaround, you can now copy and paste files into such a shared folder. If you manually create a new folder, please make sure you change the folder name within 45 seconds.

(Note: If you delete a file from a shared folder with Add / Upload permission, if the file is not empty and was created 45 seconds ago, the file cannot be deleted. However, Windows Explorer does not report any error. It will still pretend as if the file has been deleted successfully. If you refresh the folder, you will see the file was not actually deleted.

We have tried many different status codes, the results are the same. We also tested the WebDAV server in Microsoft's own Internet Information Server and was able to duplicate the same problem. So it is a Windows Explorer issue. Anyway, this is a minor issue as the file indeed cannot be deleted in this case. )