Inflated filesizes for attachments in Outlook

[Jeff7]

I'm the sort who doesn't really delete emails. Typically, they don't take up much space, and I'm accustomed to having a lot of disk space at my disposal. (It also helps to have a reference point for correspondence, and the ability to look up the history of a project in the absence of any other central database for it.)

Outlook doesn't seem to work that way though.

Examples:
- Attachment filesize: 1.03MB. But looking at the mailbox, the Size shown in the list view is 4MB.
- Email with four attachments, totaling 4.3MB: The size shown in the list view is 15MB.
- 400kB of attachment shows as 2MB in the list view.
- 306kB of attachment shows as 1MB in the list view.

I've used the Compact Mailboxes tool, which didn't seem to give any significant improvement.


Why are these filesizes so inflated?

 

[VirtualLarry]

Could it be MIME-encoded as text? And that one of the views is giving the actual extracted binary filesize, and one is giving the as-encoded filesize?

 

[Jeff7]

Could it be MIME-encoded as text? And that one of the views is giving the actual extracted binary filesize, and one is giving the as-encoded filesize?

Sorry, I kind of forgot about this issue for a bit.

How do I go about finding out that encoding information?

Example of a scanned PDF I was sent:
- The size shown in the "Size" column: 11MB
- Size of the PDF when I save it to disk: 3,012,765 bytes


Image file:
- Size column says 6MB
- The image is 1,616,898 bytes.
- View --> Source: 5,938 characters, including spaces.


Using the Compact tool doesn't seem to do a whole lot to the size of the mailboxes....at least compared to WinRAR. It reduced the size of a large compacted mailbox file by 61%.
I guess it's the usual thing: They're focusing on rapid compression time and still keeping it reasonably accessible to Outlook, rather than going for brute compression ratio.

 

[Mushkins]

What version of Outlook are you working with, and is it up to date with service packs and software updates?

I vaguely remember hearing about someone with this problem a few months back, trying to remember what the cause was.

 

[Jeff7]

What version of Outlook are you working with, and is it up to date with service packs and software updates?

I vaguely remember hearing about someone with this problem a few months back, trying to remember what the cause was.

2007.

I can head to Windows Update to see if there's anything available.
....no, just some generic driver updates, another attempt to get Silverlight on this machine, and one of the many "Update for Windows 7 for x64-based Systems" updates that appear from time to time. The latter looks to be a security update for encryption schemes, and nothing to do with office.


Here's another one:
Someone sent me a photo of a part straight from their camera. Outlook said 16MB for the email size.
I edited the email to delete the photo, but retain the email and a text description, and then saved it.

Outlook now says the email is 11MB.
But if I view headers, there's a load of data there, including what looks to be the full content of the embedded JPEG, despite the fact that I deleted it from the email.

...and I just opened another email. It's some basic HTML text, a few small social media icons, and no attachments. Outlook says it's 219kB. I just saved the entire file as an HTM, with the folder to contain any embedded images. Windows says it's all 80.7kB.
220% inflation?

If I do the same for the 11MB email, the total saved size of the HTM file and its folder is 83.1kB. There's no JPEG to be found.

 

[Mushkins]

Check out this post from superuser, it might be what you're experiencing.

http://superuser.com/questions/480996/why-does-outlook-increase-the-file-size-of-an-email

Also make sure you have Microsoft Update enabled or you won't get Office updates via running regular old windows update.

 

[Jeff7]

Check out this post from superuser, it might be what you're experiencing.

http://superuser.com/questions/480996/why-does-outlook-increase-the-file-size-of-an-email

Also make sure you have Microsoft Update enabled or you won't get Office updates via running regular old windows update.

It looks like I've got the latest updates already. Office 2007, with Service Pack 3 installed.
(Outlook 2007 (12.0.6691.5000) SP3 MSO (12.0.6741.5000))


Reason this came up today: An email came in with a 5MB PDF attachment I didn't want to keep. Outlook said it was a 15MB email.
I removed the attachment from the email. (Open email, right-click attachment, Remove.)
Now it's showing as 14MB.
The HTML source is 1766 bytes.
Same as before though: If I view the full message content/headers, there's a large mass of data still embedded in there.
After compacting the mailbox file: No change, still 14MB. It's a PDF attachment, and not an inline image, so I don't think the Superuser.com link applies.

So if I remove an attachment, it sometimes treats it like I'm removing a shortcut?

 

[Mushkins]

Perhaps it's not an outlook problem at all, but a mailserver issue? Outlook doesn't usually mess with the message headers of incoming email.

What email service is the backend running on and who's the provider?

 

[Jeff7]

Perhaps it's not an outlook problem at all, but a mailserver issue? Outlook doesn't usually mess with the message headers of incoming email.

What email service is the backend running on and who's the provider?

:hmm:
Not sure. I'm not quite sure what it is you're asking for here. I know of the term "backend."

The email's coming from the company email server.....?
Anything else, I don't know.


If it helps, this is what it looks like if I go to Message Options --> Internet Headers for the 14MB email after I attempted removal of the attachment: (Most of the PDF data has been truncated away; names and external IP addresses and such have been altered.)

Return-Path: <person@companyA.com>
X-Original-To: <person@companyB.com>
Delivered-To: <person@companyA.com>
Received: from localhost (server.companyB.com [127.0.0.1])
    by server.companyB.com (Postfix) with ESMTP id 842C9ED0005;
    Thu,  4 Feb 2016 11:49:35 -0500 (EST)
Received: from server.companyB.com ([127.0.0.1])
    by localhost (server.companyB.com [127.0.0.1]) (amavisd-new, port xxxxx)
    with ESMTP id ke+DLiWg+DcY; Thu,  4 Feb 2016 11:49:33
Received: from [192.168.1.140] (IP address)
    (Authenticated sender: person)
    by server.companyB.com (Postfix) with ESMTPA id A4050DE0004;
    Thu,  4 Feb 2016 11:49:11 -0500 (EST)
To: person@companyA.com,
 "engineering@companyB.com" <person@companyB.com>
From: Name <person@companyB.com>
Subject: Message subject
Message-ID: <56B38129.20806@companyB.com>
Date: Thu, 4 Feb 2016 11:49:45 -0500
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
Content-Type: multipart/mixed;
 boundary="------------010701010901030806010502"

This is a multi-part message in MIME format.
--------------010701010901030806010502
Content-Type: multipart/alternative;
 boundary="------------020205080505000503030809"


--------------020205080505000503030809
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit

Hello ......
**message content**

--------------020205080505000503030809
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: 8bit

<html>
  <head>

    <meta http-equiv="content-type" content="text/html; charset=utf-8">
  </head>
**message content**
  </body>
</html>

--------------020205080505000503030809--

--------------010701010901030806010502
Content-Type: application/pdf;
 name="filename.pdf"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
 filename="filename.pdf"
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 

[Mushkins]

Let me clarify. Who is the "company?" Is this a gmail account? Yahoo? Some free ISP account? A work account provided by your employer?

 

[Jeff7]

Let me clarify. Who is the "company?" Is this a gmail account? Yahoo? Some free ISP account? A work account provided by your employer?

Work account provided by employer, on our own .com.

 

[PliotronX]

Huh, I had never noticed this with newer Outlooks (2013-2016) but sure enough if I "pop out" a message and look at the properties, the message size is double the size of the attachment. There is a 30% overhead for ASCII encoding but I wonder where that other waste is going. Anywho, I have an effective autoarchive setting to keep the OST clear and an archive PST that everything older than 5 months goes to and it's easy to search either of them. It's on a VeraCrypt container in cloud storage so that I can open the PST from anywhere.

For comparison's sake, my account is homed on-prem in Exchange Server 2013.

 

[sm625]

Find the email file in windows explorer. What is the size of that file as reported by its Properties?

 

[Jeff7]

Huh, I had never noticed this with newer Outlooks (2013-2016) but sure enough if I "pop out" a message and look at the properties, the message size is double the size of the attachment. There is a 30% overhead for ASCII encoding but I wonder where that other waste is going. Anywho, I have an effective autoarchive setting to keep the OST clear and an archive PST that everything older than 5 months goes to and it's easy to search either of them. It's on a VeraCrypt container in cloud storage so that I can open the PST from anywhere.

For comparison's sake, my account is homed on-prem in Exchange Server 2013.

I came across something....I think.....that Outlook leaves some kind of space buffer inside the file, and only after some amount of time it'll decide to compact the space. Even "Compact Mailbox" doesn't do much.
(And finding any answers for this issue online is tough. Most of the matches are entry-level, which are merely introducing people to the Compact Mailbox tool.)

Find the email file in windows explorer. What is the size of that file as reported by its Properties?

The whole Outlook mailbox file? (Outlook keeps everything in a single .pst file.)
Enormous.
About 6.5GB.

One individual email:
I just saved out the "14MB" email I mentioned a few posts ago.
- If I save it out as a complete HTML file with folder, the total size is 53,153 bytes. No sign of the PDF. The phrase "pdf" isn't even contained within the contents of any of the files.
- If I save it as Outlook Message Format (.msg), it is 7,233,536 bytes. If I open that with a hex editor, there it is again: That pesky removed PDF file, still embedded within the file.

 

[Mushkins]

Work account provided by employer, on our own .com.

Have you contacted your companies IT department regarding this? They're going to be able to do a better job of looking into it than anyone here.

Could be a spam filter service or misconfigured exchange server creating additional overhead, either way, they're getting paid to fix these problems

 

[Jeff7]

Have you contacted your companies IT department regarding this? They're going to be able to do a better job of looking into it than anyone here.

Could be a spam filter service or misconfigured exchange server creating additional overhead, either way, they're getting paid to fix these problems

Checked with them....this problem wasn't anything they'd seen before.

If I send this alleged 14MB email to someone, it shows in my Sent box as being only around 15kB, and they receive it as about 25kB. The phantom data just disappears.

IT solutions also seem to be skewed more toward "format and reinstall," so I was hesitant to leave my PC with them. I do not like format&reinstall of an OS and apps, because I have numerous customizations that take a long time to get configured just right.

 

[Ketchup]

Formatting for oversized emails? Don't know why you would do that unless you are really running out of space.

Here is what I do: I get about 100 emails a day, give or take. Most are just text. After about 6 months, a majority of them get deleted. After removing them from deleted items folder, I rename my ost file and restart outlook, and let it re-download my emails from the server. Save a decent amount of space this way.

With your particular issue, you might let IT uninstall/reinstall office for you, but I wouldn't have them do much more than that.

 

[Jeff7]

Formatting for oversized emails? Don't know why you would do that unless you are really running out of space.

Here is what I do: I get about 100 emails a day, give or take. Most are just text. After about 6 months, a majority of them get deleted. After removing them from deleted items folder, I rename my ost file and restart outlook, and let it re-download my emails from the server. Save a decent amount of space this way.

With your particular issue, you might let IT uninstall/reinstall office for you, but I wouldn't have them do much more than that.

I guess I should have said "toward the format&reinstall part of the spectrum," and not that that's precisely and exclusively what would happen.

As someone who's done troubleshooting, the allure of resolving a problem with a sweeping purge is always there, but sometimes it's not worth it. (Like spending 5 hours weeding out a damned rootkit virus myself.)



It's just a bizarre problem to have.
Remove the attachment.
Attachment's contents are still lingering somewhere in the email.
The purpose of "Remove attachment" is.....???

 

[Mushkins]

I guess I should have said "toward the format&reinstall part of the spectrum," and not that that's precisely and exclusively what would happen.

As someone who's done troubleshooting, the allure of resolving a problem with a sweeping purge is always there, but sometimes it's not worth it. (Like spending 5 hours weeding out a damned rootkit virus myself.)



It's just a bizarre problem to have.
Remove the attachment.
Attachment's contents are still lingering somewhere in the email.
The purpose of "Remove attachment" is.....???

At this point I'm hesitant to even suggest any potential fixes, as we're definitely in the realm of shadow IT which more often than not causes bigger problems for the people getting paid to fix those problems.

You need to report this to IT, they're being paid to fix it, they know the environment, and we have no business telling someone to make changes on a device managed by a corporate IT policy. Professional ethics dictate this is where I get off the bus, sorry.

If they say they want to wipe the machine you can always tell them it's more trouble than it's worth and to just leave it be.

 

[sm625]

Could it be MIME-encoded as text? And that one of the views is giving the actual extracted binary filesize, and one is giving the as-encoded filesize?

That would account for some of it. Maybe the file size calculator is converting the binary data into unicode and then doubling the count because unicode is 16 bit instead of 8 bit. So you have a doubling from that plus another 30-50% from the MIME-encoding giving you a grand total of roughly 2.8X reported file size inflation. But it seems like that is not the actual amount of disk space being used.

 

[Jeff7]

At this point I'm hesitant to even suggest any potential fixes, as we're definitely in the realm of shadow IT which more often than not causes bigger problems for the people getting paid to fix those problems.

You need to report this to IT, they're being paid to fix it, they know the environment, and we have no business telling someone to make changes on a device managed by a corporate IT policy. Professional ethics dictate this is where I get off the bus, sorry.

If they say they want to wipe the machine you can always tell them it's more trouble than it's worth and to just leave it be.

Let's just say, it's a fairly liberal place in terms of IT policy, versus some stories I've read here.
I'm largely free to customize my machine to my discretion, which isn't something they offer to everyone. I have a good idea of what's permissible and what's not on a company machine. Heck, it's something that's kept me interested in working at this company. I loathe restrictive computer security.
"Here's a powerful tool, but we're not going to allow you to use it properly."
It makes me think of a Futurama episode, where someone was going to be exposed to something that'd make her really stupid: "We've also prepared a bag lunch, and some mittens" so that she wouldn't hurt herself.
"Here's a 200-piece tool set. You're only allowed to use a 1/8"-blade flat-head screwdriver and the needlenose pliers. Everything else is off-limits. Your job is to install large Philips-head screws, which is possible using the available tools."
-"But if I use these other tools, I can do things much more efficiently."
"Denied.

I'm already impatient operating computers when it comes to the sluggish barrier that is the coordination of my own hands and fingers. It gets maddening when the computer is severely locked down.



And in this case, the people in IT have never seen this kind of problem before, so even if the .pst files get wiped clean and I start fresh, it'll likely just start happening again with the next .pst file, and I'll be without my mountain of easily-accessible reference materials for the numerous projects I've been involved with.

That would account for some of it. Maybe the file size calculator is converting the binary data into unicode and then doubling the count because unicode is 16 bit instead of 8 bit. So you have a doubling from that plus another 30-50% from the MIME-encoding giving you a grand total of roughly 2.8X reported file size inflation. But it seems like that is not the actual amount of disk space being used.

And there's still the issue of the attachment removal not really removing a whole lot.
That whole experiment of saving an email as HTML+contents=<100kB versus saving the email as an email file = 7MB was certainly interesting. 7000% inflation for what should have been a text-only email at that point, given that the attachment that was allegedly removed. Weird.