The SanDisk Sansa Clip Zip is a great digital music player. It's sound quality can be first class. It's size couldn't be much smaller. The controls are easy to use and include physical buttons that you can operate by feel. Up to 40 GB of space is available for songs when an external micro SD card is added to the CZ. The CZ can play many sound formats including AAC.
A lot of purchasers are buying the CZ as a low cost iPod to run their iTunes songs. The reviews here and at other sites are full of people having problems with their CZs when they try to play their AAC music. These problems come mostly from loading music into the CZ that contains copy protection software. Years ago as computers evolved, the music industry became concerned that computers could read and make perfect copies of music CDs. So the CD manufacturers began hiding anti-copying software in the CD's music. This is called Digital Rights Management or DRM for short. In order for computer software to be able to play and copy DRM CDs, the software had to play by the music industry's rules and agree to limit copying of these CDs. This is one of the functions of iTunes and Microsoft's Media Player. When iTunes loads DRM music into an iPod during the SYNC process, it transfers decoding keys with the music and the iPod knows how to use these keys to play the music. ITunes keeps track of how many copies are made and where the copies go. The number of copies is limited. In addition to DRM in CDs, at one time, the Apple store sold all online music with DRM built in, at the music industry's insistence, but since early 2009, all Apple music is DRM free. Apple does imbed your name in the music you buy today, like a watermark, so that any copies that you pass around can be traced back to you. The CZ Does not "SYNC" to iTunes and is not programmed to use DRM keys. If you install DRM music into the CZ, it will lock up when it finds the DRM music during the Reindex procedure. It is easy to drag and drop AAC music from iTunes, either from the iTunes window or from the song files themselves from their folders. But only iTunes can transfer the keys needed to play the music.
CD music that has DRM, does not comply with the COMPACT DISC standard. IF there is no DRM present, a CD will display the COMPACT DISC logo on the CD and on the packaging. If you don't see this logo, the CD's music will likely contain DRM and cause CZ playability problems. Of 4500 songs loaded into my iTunes from my CDs, I found two albums that did not contain DRM. Only these two albums would play in my CZ (rev 17 software). The last 30 CDs I purchased, all contain DRM software and cause the CZ to lock up. So beware that the CZ is not an iPod substitute. It can not unlock DRM music. Most of your music will likely contain DRM software. You can get your DRM iTunes AAC music into your CZ by converting to lower quality MP3s, using digital to analog to digital conversion, and by using illegal methods, but all may take a lot of time. If all your music was purchased online from Apple since early 2009, you are in luck and all your music should load into the CZ. Note that some DRM music will load into the CZ's internal memory but not into external memory cards, so don't be too quick to call your microSD card bad. Also many other online music sellers still use DRM.
If your CZ has locked up due to DRM software, you need to remove the infected music. 1. Hold down the CZ power button for 15 seconds. This resets the CZ and leaves it in the off state. Don't press the power button or the CZ will crash again. Instead: 2. Connect the CZ while it is off, to your computer's USB port and delete the DRM music from the CZ after the CZ shows up as a drive. When you disconnect your cleaned CZ from your computer, the CZ will be working normally again.