i can't restore my iPod Classic

From the linked user tip...

Check your iPod with Diagnostics Mode

It is possible that your iPod's hard drive has started to fail. Take your iPod and place your right thumb on the centre SELECTbutton and your left on the top MENU button. Press down both thumbs for about 6 seconds until your iPod reboots. Immediately move your left thumb around to the rewind button |<< on the left and hold this down together with SELECT for a further 6 seconds. Your iPod should now switch into Diagnostic Boot mode. Press MENU for Manual Test, then select IO > HardDrive > HDSMARTData to reveal your stats. For comparison here are mine taken when my 6th Generation Classic was about 2 years old:

Retracts: 889
Reallocs: 12
Pending Sectors: 0
PowerOn Hours: 2202
Start/Stops: 894
Temp: Current 24c
Temp: Min 10c
Temp: Max 50c

Take a note of your results. When finished press MENU+SELECT for 6 seconds to reset the iPod again.

With modern disk drives sectors are no longer marked bad by a disk scan, if the SMART firmware detects a sector it has trouble accessing it will attempt to invisibly reallocate it to a spare area of the disk.

Note that I've only 12 remapped sectors and none pending. To help explain what the numbers mean here is an extract from the Wikipedia S.M.A.R.T. article:

Reallocated Sectors Count

Count of reallocated sectors. When the hard drive finds a read/write/verification error, it marks this sector as "reallocated" and transfers data to a special reserved area (spare area). This process is also known as remapping, and "reallocated" sectors are called remaps. This is why, on modern hard disks, "bad blocks" cannot be found while testing the surface – all bad blocks are hidden in reallocated sectors. However, as the number of reallocated sectors increases, the read/write speed tends to decrease. The raw value normally represents a count of the number of bad sectors that have been found and remapped. Thus, the higher the attribute value, the more sectors the drive has had to reallocate.

Pending Sector Count

Number of "unstable" sectors (waiting to be remapped, because of read errors). If an unstable sector is subsequently written or read successfully, this value is decreased and the sector is not remapped. Read errors on a sector will not remap the sector (since it might be readable later); instead, the drive firmware remembers that the sector needs to be remapped, and remaps it the next time it's written.

Large numbers of Reallocs or Pending Sectors (several thousand in the case of a classic) would suggest your drive is failing and that you may need to repair or replace your iPod. Check your stats after another attempt to update your iPod. If the numbers increase that again points to hard drive failure. While it won't be good news at least you'll know it isn't some random software problem and you can decide what to do next.

Anti-virus software is always changing, some of the actions that iTunes might legitimately request when restoring might appear suspicious from the perspective of the anti-virus suite. See this recent thread where Norton was the cause of a similar issue: Re: Can't restore iPod Classic 120GB.

tt2

As noted, read the user tip that I have linked to: Corrupt iPod Classic, or read the relevant section that I copied into this thread. The details are there. This is the part that you have presumably overlooked:

Take your iPod and place your right thumb on the centre SELECT button and your left on the top MENU button. Press down both thumbs for about 6 seconds until your iPod reboots. Immediately move your left thumb around to the rewind button |<< on the left and hold this down together with SELECT for a further 6 seconds. Your iPod should now switch into Diagnostic Boot mode. Press MENU for Manual Test, then select IO > HardDrive > HDSMARTData to reveal your stats.

Not forgetting:

Take a note of your results. When finished press MENU+SELECT for 6 seconds to reset the iPod again.

tt2

From Corrupt iPod Classic:

DFU Restore

If the device still won't restore normally try this method. Connect the device to the USB cable, press MENU+SELECT like a standard reset but keep holding for 12 seconds. The device should reboot as normal and then the screen should go blank. Now open iTunes and try to restore again.

tt2

Here is what Apple has to say in general regarding older products: Vintage and obsolete products - Apple Support. In addition they're removing iTunes support for older operating systems: About iTunes Store availability - Apple Support. I'm somewhat surprised if they've actively removed the ability for iTunes to download the correct firmware for older devices, but I suppose it isn't outside the bounds of possibility.

Is there an alternative to restoring? Can you wipe the contents of the device in some other way, assuming that is what you wanted to do?

tt2

What anti-virus software do you have? This can sometimes interfere with the way that iTunes operates. You could try restoring again with it temporarily disabled. Did you get a chance to check the device's HDD stats?

tt2

What are the HDD stats? The numbers may indicate that the drive has had it, and therefore you're unlikely to be able to get further with it. Or they could show that the drive is essentially OK, in which case you need to eliminate possible causes of interference, such as you anti-virus software.

tt2

Doesn't look bad at all. Mac shouldn't be over 50, but I don't think that is significant. You should be able to use the DFU restore method in iTunes to restore the device. If it won't work I'd try temporarily disabling AVG real time protection.

tt2

Rather than give up I would see if a friend can restore the device on their computer. As noted the stats suggest your device is OK, so perhaps disabling AVG isn't enough to stop it interfering, or there is something else quirky about your set up.

tt2

Well I don't know why you're having trouble, but I just restored my 6th generation 160Gb iPod classic using iTunes 12.7.3.46 running on High Sierra, so it is clearly still possible. iTunes had to download the firmware since this computer hasn't previously be used to manage this old device, and that went OK, so the .ipsw files are still online.

tt2