The full post on this is here, but I wanted to make sure that everyone saw this, since there is a lot of traffic on this issue….

I believe that a solution has been found in the Apple Customer forums…  The following command, will reproduce the plist was not a dictionary error message…

/System/Library/CoreServices/PreferenceSyncClient.app/Contents/MacOS/PreferenceSyncClient –sync –periodic

and the next command will display all the files that have any array in it…

egrep ‘^<array>’ ~/Library/Preferences/*

I do not suggest deleting these files, instead move them to a different directory.  For example, my iTunes preferences was detected as a file in question…  As well as the iCal alarmscache file….  And neither application was indicating or showing any issues…  So move the file to a different location, and test to ensure that you are not receiving a false positive….

egrep just does a pattern match, so it just scanning the files for “<array>” being found at the beginning of a line.  I hope to have this confirmed as a solution in a few hours, when I don’t see this error message in the log file any longer…