Can't replace file

When open a file stored in my WD MyBook Live 2TB and edit it, then is impossible to save the file and overwrite the old file it need to rename the file for example if I have a file named file.xls, when I open it and edit it then save in the download folder of the WD2go software, then I must copy this new file to the original folder and can’t overwrite, the software create a file called file-1.xls and need to erase manually the older file and rename the new file. Can any told me if this is normal ? Thanks

Does this happen when you open the file remotely or on the local network?