Under The Microscope

Well, Shoot

Update (August 30th, 2011): Airfoil 4.5.7, featuring Instant On 4.1, is now shipping. You can download it from the Airfoil page. With this update, Lion users will be able to grab audio from already-running applications, as well as from the System Audio device. Get it now!

Approximately 48 hours ago, we shipped version 4.5.6 of Airfoil. Unfortunately, we shouldn’t have. Since shipping, we’ve learned that the Instant On component of Airfoil has a critical incompatibility with several third-party applications on Mac OS X 10.7 (Lion). To be clear, Airfoil itself causes no problems – this issue only occurs with version 4.0.0 of the optional Instant On component. This issue may cause crashes with applications including DragThing, SpamSieve, and others1.

Because of this issue, we’ve rolled the Airfoil update back. For the time being, Airfoil 4.5.5 is once again the latest version of the app. Please continue reading for more information.

What To Do If You’ve Installed Airfoil 4.5.6

Most importantly, let’s resolve any issues you might be seeing. If you’ve installed Airfoil 4.5.6, you can and should immediately roll back to version 4.5.5, by following these steps:

Step 1: Open Airfoil and choose “Install Extras” from the Airfoil menu.

Step 2: If the Instant On component shows version 4.0.0 is installed, click the Gear menu, and choose Uninstall. Once complete, your computer will need to restart

Showing Instant On is Installed

This is what you’ll see if Instant On is currently installed.

If Instant On is not installed, just move on to step 3.

Showing Instant On is NOT Installed

This is what you’ll see if Instant On is not currently installed.

Step 3: It’s critical that you complete the above two steps. Once you have, delete your existing copy of Airfoil.

Step 4: Download Airfoil 4.5.5 from our site, install it, and use it.

Step 5: Watch for future Airfoil updates to restore Instant On’s functionality to Lion2. These updates will be even more heavily tested prior to shipping.

We hope you’ll accept our sincere apologies for both the hassle of rolling back, and any crashes you ran into. We’re working around the clock to get Instant On functioning on Lion. Unfortunately, despite our testing, it was not yet ready when it was released.

More Details

While we can’t undo the problems caused by this update, we can provide full transparency as to what went wrong.

Airfoil 4.5.6 was to be the first version to provide full Instant On support for Mac OS X 10.7 (Lion). As you may know, the Instant On component provides two powerful features: the ability to capture audio from already-running applications, and the ability to capture all System Audio at once. The release of Lion broke all previous versions of Instant On, and a tremendous amount of time and effort was required to restore this functionality. Our users were eager to have this functionality back, and we were eager to provide it.

We got this working several weeks ago, and tested it throughly. In addition to our own testing, we provided developmental versions to dozens of users who wrote in looking for Instant On’s functionality on Lion. After discovering no issues in our testing, nor hearing of any problems from our users, we released Airfoil 4.5.6 on August 18th.

Starting yesterday afternoon, the 19th, we began to receive reports of problems from users of several different applications. We also spoke directly with James Thomson, developer of DragThing, about the issue. We determined there was indeed a problem caused by Instant On running on Lion, and set about gathering more data to determine its exact nature.

Now, one day later, the nature of the problem is clear. The root cause of the issue is a change to Mac OS X, which alters the order in which critical library functions load. This can place an application in a state incompatible with Instant On, which then leads to the application crashing. While this issue only crops up with a handful of applications (older software that uses non-standard entry points), the bug is still caused by us. It’s affecting users, so we felt compelled to pull the update. Shipping any kind of incompatibility with other third-party applications simply isn’t acceptable.

What’s Next?

Unfortunately, while the nature of the problem itself is known, the solution will require some time to implement. In addition to increased testing, the update will require a redesign of the way Instant On works to fully resolve the problems we’re seeing.

For now, while the basic functionality of Airfoil (as well as Audio Hijack Pro and Nicecast) works, you will still need to restart applications to grab their audio, and System Audio capture will not available. We’re continuing to work tirelessly to get Instant On working with Lion, and hope to have more news soon.


1. A full list of affected applications follows:

• AirRadar

• Amnesia

• Apimac Timer

• Carbon Copy Cloner

• CastAway

• CDFinder

• CleanMyMac

• ColorNavigator

• Comcast Bandwidth Meter

• ControllerMate

• DiskCatalogMaker

• Doxie

• DragThing

• eMail Bounce Handler

• Find Any File

• GoFlex

• Google Earth

• HP10BII Business Calculator

• HTML-Optimizer, HTML-Optimizer Plus, HTML-Optimize Pro

• IntelliJ IDEA

• iCash

• iDupe

• iFFmpeg

• iPulse

• iVolume

• JollysFastVNC Pro

• KeypassX

• Lion Cache Cleaner

• LogMeIn

• Mac Bluray Player

• MacPilot

• MacTracker

• MaxBulk Mailer

• OfficeTime

• OmniGrowl

• Playback

• PowerTunes

• Processing

• Quay

• Radiologik DJ

• Radiologik Scheduler

• Scrivener

• SecretSync

• ShareTool

• Sitemap Automator

• Skype 2.8

• SmartSleep

• Snapz Pro X

• SpamSieve

• TeamViewer

• Tweet Adder

• Ultralingua

• Vuze

• Weatherman

• Web Site Maestro

• WhatSize

• Xscope

• Yummy FTP

If we hear reports of issues with other applications, we’ll add them here.  

2. If you’re still running Mac OS X 10.6 (Snow Leopard), Instant On 3.1 works just fine with Airfoil 4.5.5. Install it from the Install Extras window, under the Airfoil menu. 

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