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Does It Worth To Remove Duplicate Emails & Cleanup Your Mailbox?

Tags: duplicate emails · mailbox cleanup · mailbox size · PST file · remove duplicates

For the last couple of months I decided do a simple test related to duplicate emails and mailbox cleanup. To put it simple, I just let my Outlook mailbox to grow ‘natural’, without deleting unwanted messages, duplicate emails or compacting my PST file. The plan was to see how large my mailbox file will get without performing any kind of maintenance on it, then to attempt to reduce the mailbox size and see the difference.

Here is the scenario: a couple of months ago, I’ve deployed a fresh (new) profile where Outlook 2010 was going to store my emails. My Outlook profile is set to receive messages from 4 email accounts (3 business addresses, 1 Gmail personal account). I have a server-sided anti-spam solution in place, so the vast majority of spam emails are trapped on my mail server and they never reach my local Inbox – which means my Inbox is only populated with those emails that I actually want to receive (personal/business/newsletters/notifications). I use to receive around 100 emails per day on each email account – so there are about 400 new emails to be stored in my Outlook mailbox, each day (spam excluded).

Two months later, my Outlook PST file size was 541 Mb. I don’t know if it’s a lot or not, but a simple calculation says that my PST file will grow over 3,2 Gb in 1 year. Now that’s a lot, especially since Outlook is notoriously slow when dealing with very large mailbox files. As a side note, I’m not a fan of auto-archiving because retrieving archived emails is a damn slow process. Plus, I wouldn’t archive emails that are less than 2 months old, as they are simply not old enough and most of the times I end up looking for them as a reference for other emails I’m dealing with.

So, I am left with a 541Mb mailbox file and almost no spam among stored emails. Now, what do I have to do in order to cleanup my mailbox? Basically, the plan is to identify & remove duplicate emails, automated messages (out-of-office replies, postmaster-undelivered errors, etc), emails with very large file attachments. Then to empty my Deleted Items folder and compact the mailbox file in order to see the file size difference. The reason why I have to compact the PST file is because Outlook doesn’t automatically shrink the mailbox file if you erase a mail item – you have to compact it in order to reduce its size on disk.

Doing it manually may get very time consumming and it might not work well, especially since my emails are distributed in many Inbox folders using various Outlook mail rules. So I decided to test using one of the Outlook add-ins that my company sells: Weight Diet for Outlook. Ok, it may sound like I would be tooting my horn here, but it is actually a solution to a real-life scenario. There are alternative solutions (more or less similar to our product), but this post isn’t about comparing Outlook mailbox cleanup add-ins.

On my 2-months-old-541Mb-file, Weight Diet was configured to: search & remove duplicate emails, delete automated emails, find file attachments larger than 1Mb (and move them to disk while keeping a shortcut from the actual email), then compact the mailbox file. The entire process took less than 10 minutes (most of the time was spent waiting for the mailbox compact process to finalize).

The results:

249 automated emails were found & erased;

448 duplicate emails were found & erased;

64Mb of file attachments were moved outside of the mailbox file and replaced with shortcuts.

The output? My 541Mb file is now only 218 Mb. About 60% smaller! Honestly, I was expecting the program to find many automated emails (because I have subscribed to many newsletters), but I was simply amazed by the amount of duplicate emails that it found. 448 duplicate emails (in a 2 months period) means about 7 duplicate emails per day! The reason for this large amount of duplicates is probably caused by the fact that many people use to send me emails by copying (TO, CC or BCC) and sending the email to more than one of my accounts. For example, the same email was sent not only to, but also to

I guess people just want to make sure their emails are delivered, so they send them to all known addresses of that person. In return, this leaves the receiver with plenty of duplicates. If you keep all your emails in a single, big email folder, it might be relatively easy to sort them by date, then to identify and erase duplicate emails. But if you’re automatically moving incoming emails to various sub-folders (depending on the account they were received on), you will likely end up like me – having to deal with hundreds of duplicate emails received in only 2 months.

The conclusion? If you care about your Outlook speed or if you simply don’t want to waste disk space, it is always a good idea to clean up your Outlook mailbox, on regular basis. Maybe you don’t have to deal with so many duplicate emails like I do, but still I would use an automated cleanup solution instead of wasting my time manually identifying obsolete mail items.

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