While working with my Exchange 2010 environment I found that my Outlook 2010 client was missing the Archive option. After some research here are the steps to add the Archive option back to the menu
*this is registry edit work around* please be careful
Click on Start
Click on Run
Type RegEdit and Click OK
Expand To
My ComputerHKEY_CURRENT_USERSoftwareMicrosoftOffice12.0OutlookPreference (for Outlook 2007) or My ComputerHKEY_CURRENT_USERSoftwareMicrosoftOffice14.0OutlookPreference for (Outlook 2010)
Set DisableManualArchive value data to 0
Close RegEdit
Close and Start your outlook again..
And your Archive should be there