MacBook Air users might need to move their new ultra-thin laptops to keep bits moving to and fro, Apple said in a note on its support site, just one of several problems posted now that the new portable has started shipping.

Among the documents that populate the support section Apple unveiled this week for its newest Mac was one that outlined an issue between the Air and some external monitors. "If your MacBook Air is closed and an external display is your only display, you may notice a reduction of throughput for wireless networks that use the 2.4GHz band," Apple said in a document published on the newly-opened MacBook Air section of the company's online support site.

To fix the problem and get throughput back on track, Apple recommends that users try another channel on the wireless access point, switch frequency ranges, or move the MacBook Air closer to the base station.

Other MacBook Air wireless issues, according to Apple, involve slow speeds when connected to multiple Bluetooth devices and balky routers that refuse to work the Remote Disc magic. For the latter, Apple suggested that users update the firmware of their non-Apple 802.11n wireless routers to get disc-sharing operational.

Apple also confirmed that MacBook Air users who want to install Windows XP or Vista in a Boot Camp partition must have an external USB optical drive, like the £65 SuperDrive the company sells. Windows can't be installed using the Remote Disc CD/DVD-sharing software bundled with the MacBook Air, said Apple. "Be sure to connect your external USB optical drive to your MacBook Air before starting the Boot Camp Assistant," the company warned.

Other FYIs from the Cupertino-based computer and consumer electronics maker included a note that some headphones won't properly jack into the MacBook Air because of the notebook's nearly-hidden audio-out port. "Some third-party audio products, such as headphones, may not plug into the MacBook Air headphone jack because part of the connector does not fit within the port hatch," Apple admitted. "Use a third-party headphone adapter to extend the audio connection outside of the port hatch. Adapters are available at the Apple Store."

Proud MacBook Air owners should reconsider migrating from an older Mac over the default wireless connection that the Air offers, Apple added. A cabled connection is a smarter idea. "Consider using a USB Ethernet adapter on your MacBook Air and a wired Ethernet connection to your migration source for your data migration," said Apple. "This should be much faster than using a wireless connection."

And if users must migrate using wireless - perhaps because they had not sprung for the $29 adapter that hangs an Ethernet port from the Air's sole USB jack - they should pay attention to signal strength. "Use the Signal Strength meter in the upper right corner of your screen to find a location that provides the best signal to your source computer before you start," Apple recommends.

As with other recently-revamped Macs, the MacBook Air comes with one additional warning: "The Mac OS X 10.5 installation media that shipped with your MacBook Air is designed for use on this computer only and not intended for any other computer. The installer prevents this software from being installed on other Macintosh computers. Furthermore, other Mac OS X 10.5 installation media should not be used when restoring the system software on your MacBook Air."

More problems?

Last week further notes were published on Apple's website, which were later removed. The first note published, describes conflicts with older 802.11n routers. Initially the note warned of problems with earlier versions of the n-ready Airport Extreme, but this note was later removed. Apple had suggested that older Airport bases stations using a draft specification of the 802.11n wireless networking standard may implement what the company called a “wide” channel in the 2.4GHz range that could interfere with the MacBook Air, which conforms to more recent draft specifications. Apple recommended changing older base stations to use the 5GHz channels or to upgrade the base station to a newer model.

After that article, number 307288, disappeared from Apple’s website another article appeared stating simply that a MacBook Air used in conjunction with a third-party (non-Apple) 802.11n wireless routers with out-of-date router firmware may "experience issues with Remote Disc, Migration Assistant, or Remote Install." As a fix Apple recommends upgrading the router firmware.

The company had identified some other MacBook Air problems and solutions, but these tech notes were also later removed from the Apple website. One tech note identified jumpy or jerky video when using the MacBook Air's iSight camera. Apple recommended installing QuickTime 7.4 as a cure for this. The company also noted a problem with using the MacBook Air for prolonged periods. According to that note, also now removed from the site, after long periods of use the computer may become sluggish as it attempts to protect itself from overheating by shutting down one core of the CPU.

Apple also said that in extreme conditions, the MacBook Air may reduce the clock rate of the remaining core. The company's recommendation was to move the computer to a cooler area or use a cooling pad to dissipate the heat, but this note was also removed from the site.

The MacBook Air, which Apple CEO Steve Jobs unveiled at Macworld, began reaching customers this week.

This article includes additional detail of tech notes published to Apple's website at the end of January, but later removed.