I have iPod shuffle 2nd gen. 1GB, how can I autofill it with more than 70 songs?

Is your shuffle full after the Autofill? Does the playlist you selected as the source have more than 70 songs?

My 2nd gen 1GB shuffle currently has 140 songs on it, almost 100% full using Autofill. The number of songs depends on two factors. One is the average length of the songs. Longer songs take more space. A 20-minute symphony takes more space than a 4-minute pop song. The other key factor is the bit rate used for compression.

All of my songs are compressed using the AAC encoder at 256 kbps, which is Apple's current standard and the setting used for downloads from the iTunes Store. The same songs compressed at 128 kbps AAC takes up half the space. 320 kbps MP3 would use more space per song. If a lossless format, such as Apple Lossless or AIFF is used to encode, the sound quality is the best possibe, but the file size per song is MUCH higher.

If you think there is problem on the shuffle, you can try doing a Restore in iTunes. The Restore button is on the shuffle's Settings tab. This will erase the shuffle, re-install its software, and set it to default settings. If there is data corruption on the shuffle's storage that is causing this problem, a Restore should fix it.