Apple continues work to upgrade its .Mac sync service at the same time as it warns Leopard users that they require the recently-released Backup 3.1.2 software for full compatibility with the OS.

The .Mac Sync maintenance commence on 19 October and continues today, with some users still unable to implement Sync operations between their Mac and .Mac.

Users attempting a Sync operation may find the task fails, or they are presented with an unexpected "What would you like to do for this first sync?" alert.

Apple is also warning users who have upgraded to Mac OS X version 10.5 Leopard that they must also install Backup 3.1.2 for full compatibility. This update is available using software update of for direct download from .Mac. The software is available only to .Mac subscribers.

Along with Leopard compatibility, Backup 3.1.2 includes a new QuickPick for backing up Numbers documents from iWork ’08, and the iTunes Purchases QuickPick will now back up ringtones you purchase from the iTunes Store.

Customers who have purchased any iTunes Plus tracks should use the iTunes Library QuickPick to ensure that those tracks are backed up, the company warns.

Meanwhile European customers continue to complain at the incredibly poor transfer speeds they are experiencing when using the £69 per year service.

European .Mac users attempting to publish image galleries to .Mac have seen transfer speeds peaking at an insufferable 78k/s, when uploading data. Users have seen similar speeds when trying to access their own and other .Mac member's content.

In a statement issued in September, Apple said: "Apple is aware that some .Mac members in Europe have reported slow performance. Some of these members are concerned that this may be due to bandwidth limitations placed by Apple. We would like to clarify that this current performance issue is not caused by Apple’s bandwidth limitations."

However, customers on various forums and bulletin boards are clearly losing patience at the extended wait for Apple to meet the quality of service they expect to receive from the fee-based service.

All .Mac members were unable to access most .Mac services for four hours yesterday, though 98 per cent of members were still able to send and receive email using a desktop email application.