March 26, 2007 3:00 AM PDT

Tutorial: Fixing Wireless connectivity (including AirPort) problems: Dropouts, slow speed, more

by CNET staff

Troubleshooting issues with wireless connectivity can be tricky. There are a bevy of potential causes for drops in the connection, slow-downs in throughput and sporadic signal loss. As such, it's best to take a shotgun approach, throwing a number of possible fixes at the problem and hoping one sticks.

We've gathered some of the most common workarounds, listed below, along with indications for when they are most likely applicable. Issues addressed include:

Repeated dropouts (Connection lapses sporadically)
Poor wireless throughput (Slow network speed)
Router [AirPort Base station included] not recognized (doesn't appear in available networks)
Cannot connect to router [AirPort Base station included] ("Error joining network" message may be displayed)
No Internet Access (router can be connected to from client systems, but Internet access fails)
Built-in AirPort hardware not recognized
System will not automatically reconnect to network after sleep
Weak reception (poor signal strength)

Note, however, that some workarounds listed for specific issues may also work for other AirPort issues. Run through the entire list of solutions if those associated with problems you are experiencing are unsuccessful.

Toggle firmware [Useful for: repeated dropouts, poor wireless throughput]

Toggling of firmware versions (the edition of controller software stored on your wireless router) is perhaps the most successful fix for dropouts from virtually all wireless router models. By "toggling firmware," we mean trying different versions available from your manufacturer until one provides a more stable connection. In other words, a user's first attempt should always be use of the latest firmware version, but sometimes older versions provide better stability.

Unfortunately, the trick is in locating appropriate firmware updates. You can usually find the different firmware editions on a router manufacturer's Web site, but some vendors fail to offer the updates or old versions in Mac-based installer packages.

For Apple Base stations, the process is as easy as downloading and installing the desired firmware edition on an AirPort Express or Extreme Base station. Apple maintains older firmware versions on its download page, and they are easily applied from a familiar installer interface.

To check which AirPort Base station firmware revision you currently have installed, use the following process:

Launch AirPort Admin Utility (located in Applications/Utilities)
Select the appropriate Base station in the left-hand pane
The firmware will appear on the right side, as follows: "Apple Base Station... "

Toggling AirPort Extreme firmware The latest AirPort Extreme firmware version is 5.7 and this edition should be used primarily. However, the most commonly successful solution for constant AirPort Extreme dropouts is a downgrade of firmware to version 5.5.1. Reverting (or updating to) this edition of the firmware has eliminated dropouts for a surprisingly high number users.

In order to install firmware version 5.5.1, simply download the package, launch the updater application and follow the on-screen instructions, selecting your afflicted Base station.

A quick caveat: Downgrading your firmware potentially poses some significant security risks that should not be overlooked. By reverting, you'll also lose the enhancements made in the latest firmware edition, including purported performance enhancements.

Still, the astounding success with which this workaround has been applied makes it a good option for users who cannot reasonably use their AirPort Extreme Base stations for extended periods of time.

Toggling AirPort Express firmware The latest firmware edition for the AirPort Express is version 6.3, and should be used primarily. Like the AirPort Extreme, however, some AirPort Express units can benefit from a firmware downgrade to version 6.1.1. The instructions for installation are the same: simply download the AirPort Express 6.1.1 Firmware package, launch the updater application and follow the on-screen instructions, selecting your afflicted Base station.

The same security/enhancement caveats apply.

Turn router (including AirPort Base Stations) off, then on [Useful for: repeated dropouts, no Internet access]

In some cases, turning a wireless router (including AirPort Base Stations) off, then back on -- usually by unplugging then re-connecting to power -- re-establishes proper operation in the event of a dropout. This is a method of recovery rather than obviation, however.

Performing a hard reset of your router (including AirPort Base Stations) [Useful for: repeated dropouts, no Internet access]

This is an easy workaround, an is effective in a surprisingly high number of problematic cases where AirPort Base Stations will not appear in the AirPort Admin utility or refuses to allow Internet access.

Instructions for performing a hard reset involves first unplugging your Base Station from power and the active network connection, then following the instructions in the following Knowledge Base documents:

Note that after performing a hard reset you will need to connect your Mac to the Base Station via a wired (Ethernet) connection in order to re-configure it and apply the proper networking configuration via AirPort Admin Utility.

If your third-party router has a reset button, try using it for a similar effect.

Turn off wireless encryption (WEP, WPA) [Useful for: cannot connect to router, slow wireless throughput] If you have repeated problems connecting your your wireless router, try turning off any wireless encryption methods in place. For AirPort Base stations, this can be accomplished using the AirPort Admin Utility (located in Applications/Utilities).

Switching channels [Useful for: repeated dropouts, no Internet access, weak reception]

In some cases (especially when interference is at play) switching channels on your AirPort Base station or third-party router can improve reception weakened by various causes. In order to switch channels on AirPort Base stations, use this process (from Knowledge Base article #166641):

Open AirPort Admin Utility, located in /Applications/Utilities.
Select the appropriate (afflicted) base station and click Configure.
Enter the base station password if necessary.
Click AirPort, and then choose a new channel from the Channel pop-up menu.

Consult your third-party router's manual for information on switching channels. This can usually be accomplished by accessing the router's configuration page -- open a browser and enter the address 192.168.1.1.

Turn "Distribute IP Addresses" off [Useful for: router not recognized, cannot connect to router]

If you are having problems where your AirPort Base station or router is unrecognized and connected to a DSL/Cable modem, the issue may be attempted distribution of IP addresses from the AirPort Extreme Base Station, resulting in a conflict with the distribution of IP addresses from the DSL/Cable modem -- a situation which can be fixed by using the AirPort Admin Utility to turn "Distribute IP Addresses" off.

Select "Make Changes to existing AirPort Base Station [Useful for: router not recognized]

When you experience an issue where the desired wireless network looks as though it is accessible (through the AirPort menu item or the Internet Connect application), but delivers the message "There was an error joining (name of network), the most commonly successful workaround is to open the AirPort Setup Assistant (located in Applications/Utilities), then click "Make changes to existing AirPort Base Station". You will be prompted for your WEP or WPA password if one exists.

After saving the settings -- even if no actual changes were made -- AirPort access is restored in some cases.

Disable Remote configuration [Useful for: slow wireless throughput]

If you are experiencing inordinately slow transfer speeds through your AirPort Base station though a strong signal exists, you may want to try this workaround which involves disabling remote configuration on AirPort Base Stations upgraded with the firmware included in the AirPort 4.2 updater package -- resulting in the removal of a potential speed bottleneck introduced with the new firmware.

This workaround is accomplished via the following process:

Open the AirPort Admin Utility (located in Applications/Utilities)
Select the desired Base Station from the availability list
Go to the "Base Station Options" tab
Click on "WAN Ethernet Port"
Uncheck the box next to "Enable Remote Configuration."
Save your AirPort Base Station settings

Delete all "Preferred Network" listings then re-establish [Useful for: router not recognized, cannot connect to router]

One surprisingly effective AirPort Base station-specific fix for an inability to connect to wireless networks involves deleting all stored preferred networks, then re-establishing any used listings. Here's the process:

Open System Preferences and select the "Network" pane
Select "AirPort" and click "Configure"
In the "By default, join:" pull-down menu, select "Preferred networks"
Delete the network(s) you regularly use from the list
Launch the "Keychain Access" application located in Applications/Utilities.
Click on the "Kind" filter at the top, and look for "AirPort network password" entries. Delete them.
Restart, or log out then back in.
Repeat steps 1-3, this time re-adding your regularly used AirPort networks to the list using the " " button.
Restart or log out then back in.

Reset PMU/SMC/NVRAM for AirPort card power issues [Useful for: Built-in AirPort hardware not recognized]

Some data suggests that a power-related issue may be at play in the issue of AirPort cards not being recognized.

In these cases, resetting your Mac's power management unit (PMU) for PowerPC-based Macs or system management controller (SMC) for Intel-based Macs may be helpful.

Instructions for resetting the PMU for various PowerPC-based Mac models are contained in the following Knowledge Base articles:

Instructions for resetting the SMC for various Intel-based Mac models are contained in the following Knowledge Base articles:

Resetting NVRAM may also resolve some AirPort-related power issues.

In order to perform this process, shut down your Mac, then start it back up while immediately holding the following keys: Command, Option, P and R. Hold the keys down until the computer restarts and you hear the startup sound for the third time.

Turning AirPort card off then on [Useful for: no Internet access, cannot connect to router]

You may want to try turning your internal AirPort card off then back on if you are having access issues. This can be accomplished through the AirPort menu item, or using Internet Connect (located in the Applications folder)

Check for/quit third-party wireless applications (monitors/sniffers) [Useful for: slow wireless throughput, repeated dropouts]

Some third-party applications that manipulate or otherwise interact with the wireless connection may cause problems -- particularly an issue where speed vacillates quickly between normal and dismal throughput.

Among the implicated applications are older versions of coconutWiFi.coconutWiFi is an application displays you a small aqua-bubble at the top of your screen which indicates whether or not. you're in range of a wireless network. Current versions of the application do not exhibit this bug.

Reverting to older AirPort kernel extensions [Useful for: slow wireless throughput, router not recognized]

f you are experiencing dire AirPort connectivity issues after a major system update (incremental Mac OS X update or Security Update), and have exhausted all other workarounds, you can try reverting to older version of the AirPort kernel extension via the following steps: [WARNING: This workaround is risky because you should not generally mix and match kernel extensions after updates. You will also lose any AirPort-related refinements brought about by the most recent update and new conflicts can ensue. Still, in a bind, it can restore wireless connectivity where other workarounds fail.]

Download the Mac OS X combo updater directly precedent to your current system version if you applied an incremental Mac OS X update (e.g. Mac OS X 10.4.9), or your current system version if you applied a security update from Apple's download page.
Download and install the shareware application Pacifist
Drag the Mac OS X combo installer package (e.g. MacOSXUpd10.4.9Intel.pkg) onto the Pacifist application icon.
Click the triangle next to System to expand it
Click the triangle next to Library to expand it
Click the triangle next to Extensions to expand it
Scroll down and find the file AppleAirPort.kext. Drag it to your Desktop or another location (you will have to enter your administrator password)
On your Mac OS X startup drive, navigate to /System/Library/Extensions and locate a similarly named file (AppleAirPort.kext). Move it to another location for safe keeping.
Now drag the file from step 7 (the one that you retrieved from the Mac OS X combo install package) into the /System/Library/Extensions directory on your startup, in effect replacing the newer file (installed by the AirPort updater) with and older copy -- you will have to enter an administrator password.
Restart your Mac

Remove kernel extensions (Mac OS X 10.3.9) [Useful for: slow wireless throughput, router not recognized]

If you are running Mac OS X 10.3.9 and are experiencing this issue, navigate to /System/Library/Extensions and drag the following files (if they exist) to the Desktop or another location outside the System folder:

AppleAirport2.kext
AppleAirportFW.kext

Restart your Mac and check for restoration of AirPort connectivity

"Keep Looking for recent networks" [Useful for: router not recognized]

In some cases, selecting "Keep looking for recent networks" in the Network pane of System Preferences can resolve an inability to connect to local networks.

Change security protocol [Useful for: repeated dropouts, slow wireless throughput]

In some cases, WEP key-based access can provide better speeds when compared to the more secure WPA standard, or vice versa. Try switching to a different protetction method if you are having issues with one.

This setting can be changed on AirPort base stations by using the AirPort Admin Utility (located in Applications/Utilities) to configure the target base station.

Delete then re-establish wireless network [Useful for: system will not automatically re-connect to network after sleep]

You may need to delete then re-establish any encrypted AirPort network configurations in order to take advantage of automatic reconnection capabilities after sleep or restart.

Move SystemConfiguration folder [Useful for: weak reception]

Moving the folder SystemConfiguration located in /Library/Preferences, to the Desktop then restarting can resolve some connectivity issues. This workaround appears to be effective because of permissions problems that can affect the SystemConfiguration folder, and the therein contained com.apple.airport.preferences.plist file. Note that this workaround will require you to re-enter network configuration settings and may cause other lapses in functionality.

Watch for device interference [Useful for: weak reception, slow wireless throughput]

Other wireless devices operating on the same spectrum can cause interference with your AirPort connection. In fact, 2.4 GHz wireless phones and even household microwaves can cause lapses in connection or drops in speed. For information on which devices can cause interference, see Knowledge Base article #58543.

Turn on Interference robustness [Useful for: weak reception, slow wireless throughput]

Try turning on the Interference robustness option -- accessible in the AirPort menubar item, or by selecting "AirPort" from the Network pane of System Preferences then clicking "Options..."

Delete specific .plist files [Useful for: System will not automatically reconnect to network after sleep, slow wireless throughput, cannot connect to router]

Try deleting the following files from the ~/Library/Preferences/ directory (this is the Library directory within your User folder):