I get errors like below indicating that I have corrupt data between server and my ost file. I have deleted the ost and then rebuilt from server and continue to get error. I ran scanost.exe and will show log below. It provided little indication nor did it resolve the issue. Error as fould in Folders, Sync Issues: 14:01:10 Synchronizer Version 11.0.8200 14:01:10 Synchronizing Mailbox 'XXXX XXXXX' 14:01:10 Synchronizing local changes in folder 'Calendar' 14:02:36 Error synchronizing folder 14:02:36 [80004005-501-4B9-421] 14:02:36 The client operation failed. 14:02:36 Microsoft Exchange Server Information Store 14:02:36 For more information on this failure, click the URL below: 14:02:36 http://www.microsoft.com/support/prodredirect/outlook2000_us.asp?err=80004005-501-4b9-421 14:02:36 Done The link above does not provide me with any info and I have had little success searching the error code. Scanexe says it resolves some errors but then indicates this msg: 7:23:04 Scanning folder Inbox. 7:23:05 The message with the subject 'Hidden Message' in your mailbox on the Microsoft Exchange Server does not match the message in the offline folder file. 7:23:05 Scanning folder Sent Items. 7:23:06 Done 7:23:06 Performing phase 1 synchronization. 7:23:06 Synchronizer Version 11.0.8200 7:23:06 Synchronizing Mailbox 'Terry Jewell' 7:23:06 Done 7:23:06 Scanning for problems in phase 1 synchronization. 7:23:06 Scanning folder Inbox. 7:23:06 The message with the subject 'Hidden Message' in your mailbox on the Microsoft Exchange Server does not match the message in the offline folder file. 7:23:07 Scanning folder Sent Items. 7:23:07 Done 7:23:07 Performing phase 2 synchronization. 7:23:07 Synchronizer Version 11.0.8200 7:23:07 Synchronizing Mailbox 'Terry Jewell' 7:23:07 Done 7:23:07 Scanning for problems in phase 2 synchronization. 7:23:07 If problems are found in this scan, they must be fixed manually. 7:23:07 Scanning folder Inbox. 7:23:08 The message with the subject 'Hidden Message' in your mailbox on the Microsoft Exchange Server does not match the message in the offline folder file. 7:23:08 Scanning folder Sent Items. 7:23:08 DoneI have downloaded and installed MfcMapi but can not seem to find the error either. There is no msg in inbox titled 'Hidden Message' either in outlook or the exchange server.Can someone please give some direction on this synchronization error ??? Thanksnote: running Outlook 2003 sp3 on xp plateform.

According to my experience, this issue should be a network connection problem between client and Exchange Server. You action plan: 1. Check if other users(Outlook MAPI account) has the same issue? 2. Check on Exchange server side, such as event log like 9646 (KB842022) Related Articles: ============= http://www.microsoft.com/technet/support/ee/transform.aspx?ProdName=Exchange&ProdVer=6.5.6940.0&EvtID=9646&EvtSrc=MSExchangeIS&LCID=1033 842022 Event ID 9646 is logged in the application event log of your Exchange Server 2003 computer when a client opens many MAPI sessions http://support.microsoft.com/default.aspx?scid=kb;EN-US;842022 -Jason

UPDATEWe have deleted the .ost and rebuilt several times now and still get the same errors. I have ran scanost.exe see attached log/ no errors.I have deleted and repaired Emsabp32.dll Emsmdb32.dll Emsui32.dll Emsuix32.dll as well with no success.The whole issue starts when my system try's to connect and then the dialogue box opens and just sits there until I get the error or cancel the request. The only thing different from m previous service provider was the rules I created and then deleted them all.As previous scanost logs indicated errors with hidden messages in inbox I did this. http://support.microsoft.com/kb/924297Use MFCMapi to remove all rules that are applied to the mailbox. To do this, follow these steps:a. Open the folder to which you extracted MFCMapi, double-click mfcmapi, and then click OK.b. On the Session menu, click Logon and Display Store Table.c. If you are prompted to select a profile, click the profile name in the Profile Name list, and then click OK.d. Double-click the mailbox that contains the inbox rules that you want to delete.e. Expand Root Container, and then expand Top of information Store.[/FONT]Note Outlook should be in Online mode to use MFCMAPI. If you see IPM_SUBTREE instead of Top of information Store, Outlook Cache mode is enabled. Disable Outlook Cache mode before you use MFCMapi.f. Right-click Inbox, and then click Open Associated Contents Table.The Open Associated Contents Table contains the hidden messages of the Inbox.g. In the Inbox window, locate and then click the items that have the IPM.Rule.Message message class, and then click Delete.h. Select Permanent delete passing DELETE_HARD_DELETE (unrecoverable) in the drop-down list, and then click OK.I had three (3) and deleted. Restated outlook in cached mode and then did a repair of office.THIS DID NOT RESOLVE THE ISSUE>OF late we ran outlook not in cached mode and over night on a connection to server it hung and I had to kill the task.