Using Zimbra Desktop 2.01, upgraded from 1.03 (which has worked for years, with only little glitches) to 7.14, but restore and sync did not work. Un-installed, and installed v2.01: Restore from v1.03 stopped at about 3 GB, but synchronization of messages and calendar completed.
However, address book sync fails with the following message:

"Debug message: Yahoo address book synchronization failed

Exception:

com.zimbra.cs.offline.ab.yab.YabImport$1: Yahoo address book synchronization failed
ExceptionId:sync-mbox-XXXX@yahoo.com:1339029900640:33c7ab34e0cd02b0
Code:yab.999
at com.zimbra.cs.offline.ab.yab.YabImport.serviceExce ption(YabImport.java:96)
at com.zimbra.cs.offline.ab.yab.YabImport.failed(YabI mport.java:82)
at com.zimbra.cs.offline.ab.yab.YabImport.importData( YabImport.java:70)
at com.zimbra.cs.offline.OfflineImport.importData(Off lineImport.java:94)
at com.zimbra.cs.offline.YMailImport.importData(YMail Import.java:59)
at com.zimbra.cs.datasource.DataSourceManager.importD ata(DataSourceManager.java:254)
at com.zimbra.cs.datasource.DataSourceManager.importD ata(DataSourceManager.java:219)
at com.zimbra.cs.mailbox.DataSourceMailbox.syncAllLoc alDataSources(DataSourceMailbox.java:430)
at com.zimbra.cs.mailbox.DataSourceMailbox.sync(DataS ourceMailbox.java:460)
at com.zimbra.cs.mailbox.DataSourceMailbox.syncOnTime r(DataSourceMailbox.java:397)
at com.zimbra.cs.mailbox.SyncMailbox$1.run(SyncMailbo x.java:262)
at java.util.TimerThread.mainLoop(Unknown Source)
at java.util.TimerThread.run(Unknown Source)

If issue persists please post description and debug information here."

Is there any idea what can be done about this?
Do I have to go back to v1.03?