I’ve uploaded an Excel file into a colleague’s folder that I have access to. I thought that only one of us would be able to read and write to it but several times now, when I try to save my changes, I tells me that changes have been made since I opened the file and that I have to cancel, overwrite the file, or save with a new name. When I checked with my colleague, she said there was no indication that the file was already open. When I called WD they said that’s how it is and it’s a problem with my operating system?? What am I missing here?