This is a curious issue indeed. Here's what I think may be happening:
1. **Incompatibility with the file system**: Your windows PC may not be supporting the file system format that's on your micro SD cards. Can you verify if the file system used on the SD cards is compatible with your PC? For instance, exFAT, FAT32, NTFS are some file systems that Windows can handle.
2. **Outdated or corrupted drivers**: The drivers necessary for your PC to read the USB adapters may be outdated or corrupted. Can you check the driver status in the Device Manager (accessible through Control Panel)? Look under the sections "Disk drives" and "Universal Serial Bus controllers". If there are yellow triangles with an exclamation mark, right-click on them and select "Update driver". If that doesn't help, you might uninstall the driver and reboot your PC, and it should automatically reinstall them.
3. **Power Surge on USB Port**: Sometimes, if there's a slight power surge in your PC, it can stop recognising certain devices (especially USB devices)
4. **Windows Registry issue**: There could be an issue with your Windows Registry where it's not properly recognising your USB adapters. There are certain methods to fix this but it should be done carefully as incorrect registry changes can cause serious issues.
5. **USB connectors could be dirty or damaged**: Have a quick look at your USB connectors - both on the PC and on the adapters - to make sure they're clean and not visibly damaged.
6. **Operating System Bug**: Sometimes, updates in the Operating system can create temporary complications. So, make sure your system is up-to-date with recent patches and updates.
Before applying any troubleshooting steps, make sure to collect all valuable data. Please always remember that tinkering within the adapter or the pc's drivers can have possible side-effects, it’s recommended to backup or recover valuable data stored on the card on time.
