Some audio files wont play

A couple of things, one is that all the USB Thumb drives I've worked with, and have, came from the factory formatted as FAT32, even my 256GB drive. Windows can't do that, has a limit of 32GB FAT32 with its 4GB single-file-size. I got a 4TB USB drive that was formatted as exFAT, package marked for use with PC and Mac OS X, I reformatted to NTFS as my MacBook Pro died just as the newer macOS came out. Mac OS X couldn't do much more than Read NTFS without having a program installed to write to it. I use 2 things for partitioning and formatting FAT32, one is a bootable LiveCD containing GPARTED [created from a downloaded .iso file] and the other is a Linux computer with GPARTED installed with a USB Drive Dock for SATA drives, have formatted 500GB drives as FAT32.

Helmut said:

"The seemingly problematic external drive is a USB SD card adapter and of course and SD card, the external drive that's ok is a SanDisk 3.2 Gen 1 flash drive. Both appear to use the same driver."

In my experience some SD Cards and the Readers have unreliable contacts. Whether it is the Card reader contacts or the Card contacts sensitivity or both I cannot tell. As a consequence prefer to use USB flash drives.

I clean SD Card readers with a small piece of Card dampened with IPA or some such alcohol variant, also Card contacts, definitely helps. Overall preferring just not to use such Cards if possible.
I would have thought this hypothesis would be easy to check out.

I haven't had much problem lately with the SD-type cards [or SDXC cards with their SD adapter] but did back when the higher-capacity SDHC cards over 2GB came out, had to replace my pocketable adapters. I still have an old Notebook that can't read the newer but SD at 1GB still works. I also reformat in a camera as doing it in Windows may not work properly.

I'm on Windows 11, but don't think it makes a difference, and ran a test on my SDXC card which is formatted to NTFS. Created a folder with various music files and copied to the card. Using SMPlayer it played all of the file formats from it. So it must be something about your SD card or adapter. 🤷

Do you have access to another PC? Try the same thing with the same drive on that.

If a friend or relative could help... the last thing I'd do at this stage would be try random repair actions like using Tweaking.com's tool.

Another approach you might try is to boot your PC from a live boot disk (Google/search, download iso file, create - in the correct manner).

If you DON'T then see the problem with the drive, then you can suspect your Windows installation.