There is a quicker "fix". I lost a bolt on mine and it rattled like crazy at idle -- you should have seen the looks at stop ights!!
I had the same problem on the right side of my 850. I took the tire off and with a pair of long, long needle nose pliers, put a crimp in the shield which tightened it up. Place the pliers as far down as you can and give it a slow twist. Sound gone and it's been over a year now.

Good luck

As I remember this shield bolts to the bottom of the strut. Easy to replace after the rotor is removed (sorry). Consider checking the rotor for resurfacing while it is off.

Hang the disc brake caliper by string from the coil spring -- you do not need to disconnect the brake line, which means no bleeding the brakes afterward (happiness!). You need a 10MM hex key to remove the caliper bolts.

Get replacement alumnium rotor shields from a pick-&-pull before you start, just in case yours are bad. That way you learn how to remove/replace the shields on somebody else's car, not yours.

This whole service probably will take you no more than 2 hours, start to finish. A good afternoon project.

Good luck.