Contacts, AddressBookSourceSync, etc., hogging processor

Question

I'm on a clean install of Mavericks on an early 2009 8-core Mac pro.
1. After the machine is up for a while, it becomes unresponsive, and Activity Monitor typically shows AddressBookSourceSync as the culprit, hogging 100% of the CPU.
2. Console shows many icbaccountsd events every minute. Those messages state:
1/13/14 1:02:32.279 pm icbaccountsd[422]: -[ICBLocalDictionary discoverLocalIAAccounts]: Unknown high level account: com.apple.account.addressbook -
1/13/14 1:02:32.280 pm icbaccountsd[422]: -[ICBLocalDictionary discoverLocalIAAccounts]: Unknown high level account: com.apple.account.google -
1/13/14 1:02:32.280 pm icbaccountsd[422]: -[ICBLocalDictionary discoverLocalIAAccounts]: Unknown high level account: com.apple.account.addressbook -
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Got the following deleted accounts: { }
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Looking for UUID: (null) from remote key:
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Account not found during local discovery, however was not found in list of deleted accounts, will not delete:
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Got the following deleted accounts: { }
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Looking for UUID: (null) from remote key:
1/13/14 1:02:32.289 pm icbaccountsd[422]: -[ICBSyncOperation mergeLocalChanges:]: Account not found during local discovery, however was not found in list of deleted accounts, will not delete:
(Bolding is mine. That item seems telling. And I've removed numeric strings that may be personally indentifiable; I'm not sure.)
The last 4 items always repeat another 10 times (for a total of 12 times), and then the process stops briefly. Then, 3-5 minutes later, the entire cycle starts all over again.
3. In Preferences > Internet Accounts, there are a few accounts that I'm unable to delete. I have 3 active iCloud email addresses and 1 inactive gMail address. The primary iCloud address of course has all of the typical items checked -- mail, contacts, calendars, etc., etc. I noticed that the two, secondary addresses also had contacts and notes selected -- but I don't need either of those addresses to sync contacts or notes. So, I've attempted to untick those checkboxes, but generally, whenever I do, the boxes recheck themselves automatically after a minute or so.
There are also separate Contacts entries, at the bottom of the list, bearing the names of the secondary email addresses. I've attempted to delete those, but they always come back automatically.
With that in mind, I logged into those accounts in iCloud.com (on the web), and I discovered that each address had a few contacts in its own address book. So, in Contacts.app (which syncs with my primary iCloud account), I exported vcards for those contacts, just in case, then at iCloud.com, I deleted those entries from the secondary accounts' Address Books. Those items remained in the primary address' Address Book, and I have no idea why those contacts ever got assigned to the secondary addresses. But now, those Address Books are absolutely empty. I was hoping that after doing so, I could delete those entries in Preferences > Internet Accounts, but even though those address books are now empty, the deleted entries always reappear after a minute or two.
4. Another thread brought to my attention the folder ~/Library/Application Support/AddressBook/Sources. That person had similar, but not identical, problems, and he found that on his computer, this folder had a few hundred folders, each containing a Configuration.plist file that pertained to one of his email addresses. He was able to solve his problem (duplicate address collections in Contacts.app) by deleting all of the folders with plists that pointed to the problem address. When I viewed this folder on my Mac, I found it contained 13,800 such folders.
But on my Mac, the plot thickens, because in my Sources folder, a new plist folder is created and added to the folder every 20-25 seconds. So the Sources folder gains 2-3 new items every minute. (Hence, the 13,800 folders previously mentioned.) I have not been able to determine what function is propogating the folders.
5. Following the advice on another thread, I tried:
• Quitting Contacts.app
• Force-quitting AddressBookSourceSync
• Deleting the reappearing items in Internet Accounts, and
• Deleting com.apple.internetaccounts.plist -- then
• Quickly restarting the Mac.
But to no avail.
This is a clean install, so, I'm stumped. Obviously I signed in to my existing iCloud accounts, but I did not copy over any preference files for address book, etc., from the previous hard drive's backup in an attempt to avoid copying over any gremlins from the last hard drive. But for the record, I never had this problem in Mountain Lion. So, this is something that has arisen as a result of migrating to Mavericks. (No, I did not use Migration Assistant)  :-)
If anyone has any suggestions, they'd be most welcome.
Thanks.

Answer 1

I was having the "ICBSyncOperation mergeLocalChanges Account not found during local discovery" error repeatedly in the Console after adding and deleting some email accounts.  This support article fixed my problem <OS X Mavericks v10.9.1: Repeated prompts to unlock "Local Items" keychain>.