Adventures in iOS Troubleshooting

The Culprit

Apple iPod Touch (4th Generation)
Model Number: A1367
Order Number: MC544LL/A
Capacity: 32GB
11.9 GB Free Space

The Symptoms

Following the iOS 5 and 5.0.1 updates there appears to be random periodic crashes in many applications. This is independent of whether or not the device has been restarted, it affects many applications including Safari, Mail, and Settings.

Troubleshooting Steps

  1. Connected it to our iPod computer and stopped it from performing a backup (to maintain the integrity of our original backup from October when we knew the iPod was working well).
  2. “Restored” the iPod back to that backup interrupting it before it was able to put back all of the third party applications, photos, videos. Used the device for 2 weeks, no crashes, rock solid.
  3. Restored all applications back to the device. Device was rock solid for about a week and one morning, it didn’t get a complete charge and it began these periodic crashes again. No particular third party application was installed the night before.


  1. Crash logs synchronized to the host desktop’s Console application seem to indicate that with iOS 4.1 (Originally released on September 10, 2010) the iPod was dealing with a log worthy Low Memory error 1-2 times per day. iOS 4.2.1 (Originally released November 22, 2010) did not seem to increase or decrease the frequency of these “Low Memory” errors. Starting on March 8, 2011 (iOS 4.2.1), all Low Memory errors ceased until April 11, 2011 with the installation of iOS 4.3.1. Low Memory errors seemed to be back with an average consistency of around 3-5 times per day. The device was still maintaining overall stability with no noticeable application stability problems.
  2. This trend (Low Memory logs 3-5 times per day) seemed to continue right through to May 15, 2011 when they completely stopped.
  3. They started occurring again on October 13, 2011 when iOS 5 (released October 12, 2011) was installed.
  4. The frequency of these Low Memory logs went from 0 prior to the installation of iOS 5 to more than 6 instances per day. A short time later is when the application stability issues began to start with frequent Mobile Safari crashes combined with over application stability problems. On November 2, 2011, there were 99 indications of Low Memory errors with dataaccessd being the “Largest process.”

What is “dataaccessd”?

Like many devices nowadays, some applications have a visible graphical user interface, while other elements of the operating system don’t. These background processes are more commonly referred to as “daemons”.

A background process that handles requests for services such as print spooling and is dormant when not required.

The problem is that despite the assertion that daemons should be “dormant when not required” these background processes are some of the key elements that make things work on your device. Everything from print spooling (as noted above) to things like Exchange calendar and contact synchronizations as handled by ActiveSync on mobile devices are controlled by these daemons. It appears as though dataaccessd is part of that ActiveSync environment and is predominantly used to synchronize calendar entries to your iOS device.

In this case, if my above speculation is correct that “dataaccessd” is indeed related to calendar synchronization and ActiveSync there are two accounts on this device that use ActiveSync to connect to network calendars. One is a corporate Exchange account the other is a Google account. In order to continue troubleshooting this problem, I’m going to remove and recreate these two accounts. I will report back in a few days to let everyone know how that goes.