Currently Being ModeratedMay 8, 2013 4:48 PM (in response to tezoone_666)
The iPod won't appear in Finder unless you have it set to Enable disk use.
Just so we are on the same page here, if the iTunes sidebar (on left side of window is hidden), from the menu bar, under View, select Show Sidebar.
With the sidebar visible, does the iPod appear in the sidebar, under DEVICES.
Currently Being ModeratedMay 8, 2013 7:05 PM (in response to Kenichi Watanabe)
No, the iPod doesn't show in the sidebar. It's like it's not connected to my computer, and it's not charging either. When you said that I have to set it to Enable disk use, where can I find this option? I don't see it anywhere.
Currently Being ModeratedMay 8, 2013 7:18 PM (in response to tezoone_666)
You can't set it to Enable disk use, unless the iPod appear in iTunes, because that setting is on the iPod's Summary screen (in iTunes). But it should not affect this problem... I was just saying Finder may not show the iPod, unless disk use was enabled.
Try connecting the iPod to the Mac and doing a Reset of the iPod
This "reboots" the iPod. It is not erased. After the iPod gets to its home screen, run iTunes.
If that does not help, try putting the iPod into Disk Mode
Then, connect it to the Mac and run iTunes. If iTunes says something about "recovery," you may need to do a Restore on the iPod, which erases the iPod, re-installs its software, and sets it to default settings.
Currently Being ModeratedMay 9, 2013 12:33 AM (in response to tezoone_666)
In a situation with a data connection problem, there are four possibilities
Software on computer - Since you said it worked before, assuming there have been no drastic changes to your system, you can probably rule out a software problem on the computer.
USB port on computer - If you have not already, I would shut down (power off not just restart) the Mac and disconnect all USB devices, including any hubs. Start up with only standard keyboard and mouse connected (if normally used). Do a Reset of the iPod again
Run iTunes and connect the iPod (by itself) to a direct USB port on computer. The fact that you said it charges on your "stereo system" but it does not on the Mac's USB port (same cable?) makes me think there may have been a temporary issue with the USB port, or some conflict with other connected USB devices. But if this test does not help, since you have confirmed the port works with other devices, you can rule out USB port problem.
USB docking cable - You can rule out a faulty cable by trying another Apple device with the cable you have, or by trying another (known-good) cable with your iPod.
If you can rule out these three things, the fourth possibility is a hardware problem on the iPod. Although you said it charges on you "stereo system," the cause could still be the iPod's dock connector, because it has different "pins" for data and for power. Or it could be a problem on the logic board. Or something else.