Just so it’s clear, I’m talking about the menu on the Sansa m230 itself, not on the computer you’re connecting it to.
When you tap the power button to bring up the menu (by “tap” I mean press it briefly – don’t hold it or the player will shut off), it brings up a menu with the following entries:
That’s the default, anyway. If you have turned “Advanced” on under the Settings menu, you will see the following menu instead:
But we’ll assume the menu isn’t on “Advanced” mode for now. So you should see the top version.
Arrow down three times (by pressing the “Repeat/AB” button on the right front of the player, next to the screen – those four buttons can be used as up, down, left, and right, and the middle button can be used like an “Enter” key) and hit enter on “Settings.”
This will bring up the Settings menu, which shows (again assuming “Advanced” is turned off):
Arrow down 7 times (or arrow up twice, since the menus loop around) to USB and hit enter. This brings up the USB settings menu, which says:
There’s probably a check mark by “Auto Detect.” Arrow down to “MSC” and hit Enter. This will set the option to MSC, which is what you, and will return you to the settings menu. If you want, go ahead and switch “Advanced” on by arrowing up to that and hitting enter; this is handy because the device will remember where you were in the menu if too much time passes and it goes back to the playback screen.
Anyway, you can either get back to the main menu by pressing left, then get back to the playback screen by pressing left again, or just switch from the menu back to the playback screen by tapping the power button again.
Edited to add: Also, if you hit Menu and then Information, it will display (among other things, like the memory used and the number of songs and audiobooks you’ve got on the player) the current firmware version of your player. Mine says “-2.2.1A,” as in negative two point two point one A in case that negative sign is hard to read. They haven’t had a firmware update in a long time, but if your firmware version is different you might want to check the Sandisk website anyway.
Good luck. Let me know if this fixes your problem, or if there’s some step that you can’t do because your player is different from mine in some way.