Comment 1 for bug 575732

On my installation I also had the missing "Inbox" entry in the indicator menu. After some debugging I found out that it was caused by the fact that I had some disabled pop accounts. I found the place inside the code where the entry got disabled and changed it so that the Inbox entry is never disabled when pop accounts are configured (patch is attached). The solution might not be perfect (I think there's some code missing to disable the "Inbox" when all pop accounts are disabled), but I think it should improve the current behavior for most people affected by this bug.

If you don't want to compile the package on your own you could also try to make sure that there's no disabled pop account and check if this brings back the "Inbox" entry...