We have an Exchange Server 2007. One user, with Outlook 2010, has started receiving duplicate emails. It's not every email - just occasionally at random. The emails are from other internal users. What could be causing this? Thanks in advance...

The user might be getting the duplicate emails mainly by two reasons: 1. Email forwarding is set at Exchange or Outlook of other user 2. User is getting an email to his name as well as from a Distribution group.Regards from ExchangeOnline | Windows Administrator's forums

Neither of these is the case. Any other possibilities? Thanks

Does Message Tracking show the user getting 2 messages? If not, I would consider recreating a new Outlook profile, or closing Outlook, deleting the existing .ost cache file and re-opening Outlook to create a new one ( assuming Outlook is in cache mode)

No, message tracking doesn't show the user getting 2 messages. Outlook is in cache mode. Can I just have the user find file named outlook.ost on his computer and delete it, or is there more that he has to do? It seems that scanost.ext isn't available with Outlook 2010, correct? Thanks for your help.

Yep, just have the user close Outlook, find the profile's .ost file and re-open Outlook.

Hi Linda, Can this issue be reproduced? Does the affected user have any mobile device or delegate? Dies the affected user imported message from PST or be moved to another database? When did you notice this issue and what happened before? thanks. Fiona Liao TechNet Community Support

Fiona, No, it can't be reproduced because it doesn't always happen. The user has a BlackBerry that syncs with his email. No imported messages. The user just told me about it last week. He said it's been happening for "a few days". This user is out in the field. I don't think he has installed anything new, etc. I haven't asked him to find and delete Outlook.ost yet. I don't have a file by that name on my computer, but mine is XP, not Windows 7, so maybe that's different. Thanks, Linda

There is a known issue on Blackberry based on my research: http://supportforums.blackberry.com/t5/Device-software-for-BlackBerry/Receiving-duplicate-email-messages-when-using-the-BlackBerry/td-p/79936 Generally we will disable Blackberry and keep on monitoring for a period of time. If the issue continues, then Blackberry is isolated; otherwise, the blackberry is highly likely to be the cause. You may also refer to Microsoft article below to see if you are in the similar situation: http://support.microsoft.com/kb/885870 hope it is hlepful.Fiona Liao TechNet Community Support

Hello Linda. You are receiving duplicate emails in outlook 2010. Don't worry change some setting in your outlook. follow these steps: 1.On the Tools menu, click E-mail Accounts. 2.Click View or change existing e-mail accounts, and then click Next. 3.Click your POP3 e-mail account, and then click Change. 4.Click More Settings. 5.On the Advanced tab, click to select the Leave a copy of messages on the server check box, and then click OK. To know more about remove duplicate emails in outlook 2010 I refer this link: http://support.microsoft.com/kb/885870. In case you are not remove your duplicate emails after change setting in outlook. This can be accomplished by using some third-party software such as: Kernel for Outlook Duplicates Remover Software Accurate Outlook Duplicate Remover