My PC has two drives: I use one for applications, downloads, temp stuff; the other for my "permanent stuff" such as pics, docs and sometimes music. Today, checking the "data disk" there is a folder with a hex-name, content is an app called MRT. I would not have placed it there but I do recall there were a shyte-load of MS updates yesterday. A google check seems to indicate it's important to MS Security Suite. This is the first time I've ever seen a folder, on the data disk, that I did not create. I don't mind the app, if its necessary, but I do mind it phcking up the fung-schway on the data disk. Any, relevant to the app, suggestions? ETA: according to one site, the MRT is installed every time (an) update(s) are installed, and it runs ... once(?) It is supposed to delete itself after it runs but occasionally it does not so it's safe to delete it. Makes me wonder how many other (temp) files MS has scattered on the primary drive.