iPhone sync problems continue under iTunes 7.4.2: device not recognized, data doesn't transfer

Serious issues with syncrhonization of iPhones persist under iTunes 7.4.2 (also existing under versions 7.4 and 7.4.1) an update many hoped would alleviate the problems. Among the widespread symptoms:

• The iPhone is not recognized by iTunes, never appearing in the left-hand pane
• iTunes fails to transfer all music, contacts, calendar data, or other items to the device.
• iTunes times out when attempting to transfer data to the iPhone
• iTunes crashes while transferring data to the iPhone

Several solutions for these issues are contained in our special report on troubleshooting iPhone syncing, though they have not proven successful for all users. Some typical reports from iPhone Atlas readers:

• "I synced successfully a couple of times after downloading 7.4.2. Then, just now, I synced again and couldn't get past syncing Calendars. And iTunes still freezes after connecting my iPhone to the dock." -- Daniel
• "As per your request on the site, I'm writing to let you know I'm yet another person with persistent (and increasingly frustrating) problems syncing my iPhone ever since the 7.4.x updates of iTunes. Problems started with 7.4 and continue unabated with 7.4.1, which was surprising, since I'd assumed 7.4.1 was a quick bug fix for 7.4. Apparently not."
• "I have these sync issues. Only on my iMac at work. Before the iphone Used to sync only once a day similar to The post. Now nuthin. Itunes either locks up or nothing. I have latest iTunes installed. Have reinstalled --- no luck. Works fine on my two other PCs." -- Brett Winston
• "I recently updated to iTunes 7.4.1 and now my iphone has problems syncing everytime.  Sometimes it will work. Then it will hang and freeze almost every other time.  Only way to get out is to cntrl alt del and end itunes.
• "I can not get my iPhone to be recognized by iTunes in windows when I am running it in Parallels desktop on my Macbook Pro. The when I turn off windows the iTunes in Mac picks up the device. I was able to authorize the phone via iTunes in Windows but nothing else."
• "My iPhone is not updating the bookmarks, addresses, mail, or iCal settings since the update 7.4.1. I even tried restoring it but nothing will help." -- Bryan James Whitley
• "Syncing became problematic almost immediately. After three attempts it was completed except for music. After many failed attempts amid some successes, I deleted and then reinstalled the latest iTunes software, yet the same issue persists. Only occasionally does the syncing actually work. At least it does that often enough for me to get by. Nevertheless, it is frustrating. I continue to get 'timed out' and 'the required disk cannot be found' messages. The greatest amount of failure is with syncing music, which as a practical matter is not very important to me, but it should work. The only way any music has synced has been to do so manual. Recently, I changed all syncing to manual, but that doesnâ??t seem to have helped much."
• "After troubleshooting, restarting both iPhone and iMac, changing USB port, trashing iTunes and reinstalling iTunes 7.4.1 then restarting again, iTunes still does not recognize iPhone." -- Bette J. Kindberg

If you are experiencing similar issues or have experienced success with a workaround, please let us know.