Could be wiring as well I know if I go into a hardware store all the stud finders start ringing!!!! Lmao Anyways!!!! It is probably wires, you could try moving it higher and see what happens or try a different wall.

Stud finders don't actually find studs. They find changes in reflected (inaudible) sound waves. So, there is something there that is more dense than the sheetrock (or whatever) you have over it. Could be pipes (probably not unless you're drilling into a "wet" wall, usually reserved for behind toilets/showers/tubs), could be you've got metal or metallic studs (some construction, especially high-volume housing), could be wires just in the exact place you're scanning. Try scanning above and below by about a foot. If you're still getting a metal return, you might want to consider relocating your project.

Also try measuring between the 2 studs your finding, should be 16 inches. If it’s not, your most likely finding something other than studs. If they are 16, read that first comment again.

Might it also be drywall screws?

You'll always find metal on studs because there are always drywall screws. Move the finder vertically. If it stops beeping and starts again a few inches later, it's screw heads you're finding. If it screams continuously, it's more likely something else. Electrical outlet boxes are generally attached to studs and the wire or conduit may be run vertically along that stud. If you can see an outlet just to either side of where you found the stud and your stud finder gives you a continual metal / electrical signal on that stud then you probably have a wire running down that stud. Pipes might also cause a continuous alarm from the stud finder when moving vertically along the stud, or they may be horizontal and pass through it.

Could be, but probably not, unless you're only scanning a very small area. Drywall screws are usually too small for a "stud" sound return on the stud finder

If you find it detecting metal intermittently along a straight vertical (same vertical line as the "stud" setting), those are likely metal drywall screws. If the device senses both "stud" & "metal" continuously, then I would expect there are metal studs, which is common in modern construction of larger buildings.

In the interest of “covering all bases” a few general trouble shooting tips to make sure the stud finder is functioning correctly—

1. have you tried changing the batteries to ensure a fresh set?
2. have you tried it against a known empty area to ensure it reads empty as it should?
3. did you hold it against your chest and press the button eliciting the “stud found” beep and say “yep, it’s working” in front of your significant other (or pet if no significant other available)

I find cheap stud finders (which is all?) to be extremely unreliable. Return it if you can... I just use a small high-strength magnet (I usually grab a OXO bag clip with a strong magnet that lives on our fridge) and rub it across the wall lightly grazing the surface. It will stick to the drywall screws. mark them then scan up and down to make sure you find more to confirm its a stud and not a random screw from something else... Remember they are usually on 16" centers (in the US) but can be on 24" centers for some interior (non load) walls. They can also be closer than 16" when an extra is needed for a corner or a intersection with another wall, etc.

And, its confusing for everyone... The "Pro" that mounted the microwave in our kitchen attached it to the 3" PVC drain pipe in the wall instead of a stud... found that when renovating the kitchen...

It sounds like you may have an issue with the sensitivity of your stud finder, as it is detecting metal in the same spot as the studs. The metal option is likely detecting something else in the wall, like pipes. Try increasing the sensitivity of your stud finder to see if it will pick up the studs more clearly. If that doesn't work, then you might want to invest in a different stud finder. There are many reviews in this subreddit about various stud finders that can help you make the best decision. Good luck!

If you start from an inside left corner.. you should be able to go 16” (on center) and make a little pencil mark and go from there.

Get a magnet, use it to find the drywall screws in your studs. Studs found.