Knowledge Base/Solutions

After Lion Upgrade, Computer Gets More and More Sluggish During Use

Jason Dietrich
posted this on January 25, 2012 09:36 PM

This solution was found at

I clipped the relevant part. Basically, the problem is that the computer boots up fine and starts to work ok. After some time, it starts to become very unresponsive with spinning beach ball and delayed input. If you look at the Activity Monitor, a process called AddressBookSourceSync is taking up all CPU or if AddressBook is launched, it is using many gigabytes of real memory.

"She told me that Lion's Address Book now used CardDAV instead of the previous structure. As such, the OS needed to perform a conversion on my AB data. Occasionally, the conversion burped on a record. (My word, not Apple's.) This caused the AddressBookSourceSync process to become a runaway application. (Her exact words.) Her solution was to:

- Export all contacts to a vCard file for safe keeping.

- Delete ~/Library --> Application Support --> Address Book.

- Reboot.

- Open System Preferences --> iCloud. Enable Contact Syncing.

- Click on Merge Data.

This caused my system to sync with my iCloud account. It did. It took just a minute or two. All of my contacts appeared in AB. I opened Activity Monitor and watched AB's memory usage for several hours. It was stable. AddressBookSourceSync never appeared."


Comments latest first

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Jason Dietrich

Thanks, ~ added.

October 05, 2012 10:17 AM
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Felipe Sardi Cruz

I did not find the Address Book in that folder but I did find it in ~/Library/Application Support/  (that is in the home folder)

October 05, 2012 09:47 AM