After sending email using outlook 2010 in an exchange 2010 - 2008 r2 environment, the sent mail does not appear in the sent folder. This is a random issue. The problem does not happen all the time. Plus the same email addresses - sometimes show up in the sent folder and other times do not. The only difference within a normal Exchange setup, we are using PST to do local archiving of older emails.This maybe unrelated to the problem.