Impossible 'modified' dates on files - how?

Going through some folders on my laptop, there are a number of .wav files that I created myself on a digital piano I bought in late 2015. The weird thing is the 'Date Modified' column shows they were modified in 2013, which I know is impossible because I had no digital piano in 2013.

The 'Date Created' column shows 2017, which makes sense. These files have been copied to a USB stick once or twice, but I can't see how that would make the modified date appear as being 4 years earlier.
No one else has access to my laptop; no malware, yada yada yada.

Any ideas on how this can happen?

I double-checked the date when I bought my piano, and it was in February 2015, a few months before Win10 was released. And yes, I was using 8.1 at the time.

The files were created (recorded) directly to a USB stick that connects to the piano, then transferred to my 8.1 laptop, and later back to the stick. So it's an 8.1 glitch of some kind?

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I'm going to assume the answer to my question is yes.

My first suspicion is the clock on the piano is off? Have you checked that?

Moonwalker said:

My first suspicion is the clock on the piano is off? Have you checked that?

There's no clock on the piano.

cbiweb said:

There's no clock on the piano.

Well, if it has a USB connection, it has an internal clock. All digital equipment does. I don't mean a clock to tell you what time it is. I mean one that tells the processor when to click and process information. That clock would also have a date and time set in it. Do you use the piano to create music files that are saved onto the USB?

EDIT: Sorry, you just said that's what you do, didn't you? If you can use the USB connection to connect your piano directly to your computer, you MAY be able to get the piano to mount in Windows. From there, you may be able to access and check the piano's clock system and correct it if it's wrong. I would check piano's manual for more information. (Disclaimer: I actually have earned a Music Tech degree for stuff just like this. I wouldn't dream of pretending I know things I don't, nor would I fail to share what I know if it helps. )

Moonwalker said:

...I mean one that tells the processor when to click and process information. That clock would also have a date and time set in it. Do you use the piano to create music files that are saved onto the USB?

Oh, LOL, I see what you're saying. haha.

Yes, the piano can record my performance, and I save it to USB. So yeah, an internal clock is definitely there. No idea how to check it, though. But chances are that could be the culprit. Kind of annoying since I now have no idea when I actually made the recordings.

Check my edit. We cross posted. I have to go at the moment. Hope it helps.

By the way, if you DO manage to figure out the clock is wrong, take note of how far off it is. Check the dates of the files you've created so far and do the math, then you'll know exactly when you wrote them.

Moonwalker said:

Check my edit. We cross posted. I have to go at the moment. Hope it helps.

Cool. Yeah I'll see what I can do there. Thanks!

Cross posted again. LOL See my second edit.

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Another thing I just thought of is that if your piano can't be directly hooked up to the computer, there is most likely a way to check and set the clock time using a weird combination of buttons and possibly even keys. If you no longer have he manual, you might be able to find it somewhere on the web. You'd be surprised what I've found after losing my own.