External storage via USB doesn't work if you already have micro SD card inside

[NINJER]

As title suggests.

I have a Samsung Galaxy Tab S8+ with a Samsung Evo 256GB micro SD card installed in it.

If you plug in a Micro SD card reader or a SSD or a HD it will not open in your files app.

However if you discount your internal SD Card and plug in a external storage device, it will then mount.

This is frustrating as I bought a 128GB tablet instead of a larger model, and use Micro SD cards to transfer media quickly, no internal storage to move media back and forth.

[Derdle]

Are you adverse to using cloud storage?

[NINJER]

Why would I use cloud storage to watch 4k movies on my tablet when travelling when there is no good network.

[Derdle]

Context helps. Use a powered usb hub that takes 5v power, find a power bank on Amazon that can deliver 5v power, connect your card reader and the your tablet to the hub and you should be able to read from the card at its marketed speed, as long as your card reader can keep up.

[NINJER]

You're not understanding The situation. The card reader works, when you unmount internal micro SD card, but where do I move my files to when internal storage is full and my internal SD card is unmounted.

[Derdle]

You're not explaining your problem effectively.

[Troubadour]

Couple of ideas
1. Check if you can see both usb and sd card in File Manager, if so you can do copy and paste.
2. Inlikely given your description, check your usb cable connection allows both data transfer and charging, not just charging.
3. If doing usb transfers in one place, e.g. home desk, invest in a cheap device and connect beteeen the two using wi-fi direct or possibly bluetooth.
4. Look for usb to bluetooth adapters, I don't know if any are designed for your type of use.

[NINJER]

You can't if you unmount SD card, insert external storage device via usb, then try and remount the SD card it spins forever and you can't do anything till you restart your device.

If I plug in external storage device whilst having a mounted SD card it does not allow you to change what to do with the USB drive, it only lets you click power the usb

[Troubadour]

One more thing to try.
In developer options under Settinhs change Standard USB mode from charging to Transfer Files
Use Google on how to activate developer options

[Troubadour]

Ignoring the fact that this promotes a particular device, some of the actions suggested may be worth looking at
https://m.youtube.com/watch?v=e4GXU0XC5yE