Computer not recognizing MP3 player

first off check the cable your using it might have gotten broken then check the mp3 player and see if theres anything blocking or wrong with the mp3 players charging port

Disconnect from pc, go into sansa menu to USB then press center. It's probably set to MDM. Scroll to MSC, press button. Reconnect to pc & it'll probably show up
Hope this help you

try going to "my computer" on your desktop and it should show an unkown device thats plugged into one of your drives

try getting a new conector

Go into My Computer and see if anything pops up once you plug the Sansa in. If it pops up open it up from there. Sometimes this kick starts an Mp3 to install itself.

Hi,
You can try few simple steps like changing the USB ports, turning off & turning on the mp3 player and then reconnecting it, and then changing the USB mode on device: Menu --> Settings --> USB mode: MSC or MTP
If these don't work, try the steps here: Sansa e250 Not Detected in PC 

i have the same SANSA e260.....and the same problem....its easy just turn on your sansa then push the menu botton, slide the wheel in the center and at the end of the options say USB enter there and change usb mode from MTP to MSC mode.....and ready

Change the Rip settings in Windows Media Player to convert the CD to mp3 format and then re-synch it - it will work. WMP probably synched it as a raw CDA, which the Sansa cannot recognize.

-Tha Mp3 Doctor

I think I have a solution. First you turn on the MP3 Player and then go to the menu. Go down to settings. Then, go to USB. Go down to "MSC" and hit the middle button. It should take you back to the settings menu. That means you successfully changed that setting. Now plug the MP3 Player back into the computer and open up "My Computer." It should show up. I hope this helps!

We have two laptops and one desktop in my house and two 2GB Sansa c250s. My laptop recognizes my sansa c250 differently than our family's desktop (i.e. on the desktop i can't view certain folders/ music files that i transferred from my laptop to my player). The second laptop doesn't recognize mine at all, but it DOES recognize my sister's sansa c250.
my suggestion? try a different computer! and then KEEP using that computer for adding/ deleting files.