I have a USB stick that is also a voice recorder. I've used it quite a few times.

Until now, I've accessed the audio files through Windows XP on an old machine (so old you can't put Linux on it or even update Windows). The computer saw the USB and the files appeared. No problem.

As the hardware was obviously failing, I recently binned that system.

A couple of days ago, I needed to make an audio recording and did so, using the stick. I assumed there would be no problem with Linux. After all, I have several USB sticks that work with anything.

Wrong. I cannot access it. Using lsusb in terminal, Mint sees it but no more. It does not appear elsewhere. Nor it seems can I mount it.

Any suggestions as to how I can access the audio file? It could prove to be important.

The local computer shop suggests Testdisk, but I don't really want to start installing powerful software like that when I don't understand it.

*I have assumed that the stick itself is in working order. It was cheap so I wouldn't be surprised if it has itself failed.

Just because the recorder has a USB port does not make it a mass storage device. I used a Sony voice recorder (just because it was available) for a special project many years ago that was only accessible via its Windows application program.

Not being "seen" in the output of lsusb command is not a good sign. Check the output of the dmesg command after plugged in to see if it is actually recognized as beng connected. It might be a MTP device and depending on your distribution/version you might need to download some mtp utilities including a MTP FUSE filesystem to be able to access the files from a file browser. If it is MTP, XP has builtin support so it appears like a drive in the file browser just like a music CD.

"a USB stick that is also a voice recorder"
Exactly what is it?

Normally gizmo's have two parts. One is some way to access the internal memory. The other is some secondary use. For example hotspots run like that. You can use hotspot and you can access it's memory.

Testdisk would not be what I'd start with.

lsusb and then mount would be what I'd use.

Two ways to access usb devices usually too. Older and newer ways.
Your usb cable has to be perfect.
You have to have usb rights in linux. Not always given by default.

Something also to consider - does the device itself have a 'switch' for accessing it? I remember some older smartphones, mp3 players, and voice recorders you could set a 'mass storage mode' on the device and it would show up like a thumb drive, but limit what else you could do with it (e.g. no software sync to its Windows applications, no ability to update its firmware, etc) or a 'normal' mode where it interfaced through a specific program. Probably it wouldn't hurt to let us know more about the device itself if you know.

Also, and this may be obvious: do you know the USB port on the computer you're testing this on actually works properly?

This is what lsusb gives me:
Bus 003 Device 005: ID 10d6:10d6 Actions Semiconductor Co., Ltd

I know it's that by a simple process of elimination.

It does not pop up as a drive in Computer. I tried mounting it, but no go. As I said initially, it works fine with XP, Windows 10 sees it but will go no further, and Linux is a complete no-go.

It's nothing but a small USB with a pinhole for a microphone, an on/off switch and an LED. It's literally no bigger than your thumb. Very basic, but surprisingly good.

The Port itself is good - I've tested it with several other USB sticks and moved the one in question around several Ports.

I missed the W10... If XP works but not Windows 10 I would guess the recorder needs a driver.

The device is not in the USB data base or is not reporting the correct ID.

https://usb-ids.gowdy.us/read/UD/10d6