894065 Exchange ActiveSync cannot synchronize items in a store when the virus scanner on the Exchange Server 2003 server is configured not to scan that store
At last, a hotfix!
Source: https://support.microsoft.com/default.aspx?scid=kb;en-us;894065
Microsoft Exchange ActiveSync cannot synchronize items in a store when the virus scanner on the Microsoft Exchange Server 2003 server is configured not to scan that store. For example, this problem occurs if you configure the virus scanner to scan the public folder store but not the mailbox store. The items in the mailbox store cannot be synchronized.
RESOLUTION
A supported hotfix is now available from Microsoft
Date Time Version Size File name
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16-Jul-2005 01:53 6.5.7233.38 3,270,144 Mdbmsg.dll
04-Jun-2005 01:56 3,304 Redir.asp
16-Jul-2005 02:27 6.5.7233.38 5,177,344 Store.exe