Windows 7: 2 mails merge on outlook 2010

I am using MS-Office 2010 with OS as win 7 professional edition.I have configured my mail id using IMAP in office 2010.My mail server is zimbra which supports both IMAP and POP3.My webmail i.e. ZCS works fine.
Issue on outlook: When i send an email say to id abc@efg.com with my signature.When he receives an email it has some different signature but mail id and content remains the same.Sometimes subject and content has also got changed.
This type of behaviour is random.Also my collegues are facing this issue sometimes.
Kindly help

Hi rupash,

I think you have to do some mistake to configure your email accounts properly, So you can try to setup again by help of following steps: Set Up Outlook 2010 for IMAP or POP Access to Your E-Mail Account

Hi Marshalhubs

thanks a lot for your reply.

The setup which we have is new.All the systems have newly installed win 7 and outlook 2010.Also if it was a configuration issue i think i should face the problem very often.Kindly correct me if i am wrong.

Please help and suggest.

Kindly suggest and reply..I am facing many issues due to this problem.