David,
I would say that it is a similar way of storage.
I just feel very hesitant to use Avast again if this is what will happen when I scan my PC again and it finds a virus in my inbox. Any ideas of how I should handle it in the future? Just ignore the warning and try to find the infected email and delete it? If I didn't know better I would say that it is a bug in the program that allows this to happen. Don't you think?
Thanks for the responses!
I don't think that you should ever delete something until you identify exactly what it is and where it is. The safest course of action is repair (and this instance since the infection is within a file within a database, it can't be repaired by avast or other AVs), then the move to chest option. This at least gives the fall back of moving it back to where it came or recovering data/emails (but you don't know which is the infected email).
I think that you were unlucky in having a virus already in your system/emails when you installed avast (your previous AV let you down here).
The inbox is the most vulnerable to infection/corruption/deletion as its the mailbox that is open most of the time and if you experience a crash, it is likely to be corrupted.
That is why my inbox is not a storage location, just a tempory location until I have read and actioned the email, then it goes into a more appropriate, personal, newsletters, receipts, etc. There are just 4 emails in my inbox at this time so if I lost that no problems.
I also regularly backup (daily) my email folders, find where they are stored and copy them to a backup folder, if you lose something you have only lost one days worth of emails.
Back it up or lose it.