During an iTunes sync, are MacBooks prevented from going into sleep mode?

Question

I want to know this as I sometimes leave my iPhone unattended while syncing and I want to make sure that there's no cut off to the iPhone sync.

Answer 1

Your MacBook shouldn't go to sleep while iPhone sync is in progress. iTunes' sync needs to copy files from your Mac to the iOS device, and vice-versa. In either case, your Mac is accessing the hard drive.

Refer to Mac OS X: Why your Mac might not sleep or stay in sleep mode – Apple Support. This section roughly halfway down the page is relevant:

Open applications can affect sleep

Software that accesses the hard drive will delay sleep mode until it is either quit or done accessing the drive. For example:

• Songs playing in iTunes.
• A movie disc playing in DVD Player.

[... lots more detail in the article ...]

In your case, songs aren't playing in iTunes, but iTunes does keep accessing the drive as long as the sync is in progress, which should keep your MacBook awake.