Sunday, May 31, 2009

Outlook Thread Compressor: New Escapee from Redmond


Nothing I like better than digging up an internal tool of Microsoft that gets released quietly on the web for free.

Particularly when it comes with all kind of dire warnings and a back-story about the legal-team at Microsoft not allowing it to be released on the Downloads pages by the developer for general consumption by the public for fear MS would be sued because it actually might lead folks who misuse it to delete their emails.

Fun!  Sign me up!

Outlook Thread Kompressor

Last night while stumbling across some new IT sysadmin blogs I found some recent references to this internal Microsoft tool for Outlook.

It is the coding genius of a Microsoft employee named Ewan Dalton.  And I think the only thing that would make it more impressive were to use the German word for “compressor…”

Thread Compressor is an add-in to Microsoft Outlook, which removed unnecessary emails from a "thread" - reducing the amount of storage required (maybe keeping your mailbox within its size quota) and reducing the number of emails you need to read.

TC was developed inside Microsoft from 1999 onwards, and attracted a large following (up to 30,000 users) but has never (officially) been made available externally, due to the fact that it will delete data unless it is configured not to. I've decided to share it more widely now.

Let me say that again: Thread Compressor, as it is configured by default, WILL DELETE DATA FROM YOUR INBOX.

If you choose to download it and use it from here, you do it with the author's blessing, but it's completely at your own risk and Microsoft cannot be held responsible for what it does.

If you're in any doubt about this, then do not use this tool.


Is that cool or what!!

It even supports logging of actions taken, and some advanced exception rules.

Basically what it does is to use internal-to-Outlook message id’s to figure out the parts of an email thread.  It then deletes all those emails that exist as part of a larger email thread version.

I’m horrible about this.  I will keep my original (sent) email, and the reply, and all additional replies as separately-saved emails.  That is likely one reason why my primary Outlook PST file is so very, very large.

Now, depending on your email-retention guidelines in the workplace you might need to save all those.  But if not, this tool promises to clean house and whittle down all those multiply-appearing instances.

Installation is not for the feint of heart.

The application itself works on all Microsoft Outlook versions (Outlook 2000, 2002, Office Outlook 2003, 2007) for Windows running on all versions of Windows post Windows 2000.

From the program page:


* Firstly, download the ZIP and save it locally.

* Create a folder you'll find again - I'd suggest C:\Program Files\Thread Compressor or similar.

* Start a command prompt - WindowsKey-R then
cmd <enter> (though if you're on Vista or Win7, just press WIndowsKey, type cmd, then right-click on the cmd icon and choose "Run as Administrator")

In the command prompt, type:

cd c:\program files\thread compressor (or wherever you put the files)

regsvr32 comdlg32.ocx

regsvr32 msflxgrd.ocx

regsvr32 tabctl32.ocx

regsvr32 threadc4.dll

Download the latest CDO file from here, save it somewhere, expand it out and run the install from the ExchangeCDO.msi file.

Now start Outlook: how you actually install the addin will vary depending on your version of Outlook, but try:

Tools | Options | Advanced | Add-ins,

or Tools | Trust Center | Add-ins | [then hit Go to manage COM add-ins]

and add the threadc4dll file manually. If it's successful, you should see Comrpess Threads on the Tools menu, and you'll get a splash screen next time you start Outlook.

Got all that?

By the way, “CDO” stands for the Collaboration Data Objects package.

Like I said, a geek’s tool only for brave geeks.

What surprised me even more was that there were quite a few other posts referring / reviewing / remarking on this neat utility.

Outlook Thread Compressor download now available – Ewan Dalton’s (creator of Thread Compressor) The Electric Wand blog.  Good overview of the tool from the developer’s perspective.

Thread Compressor for Outlook - do you want it? – Ewan’s The Electric Wand blog post from 2007 where he teases about an earlier version and provides some credit to others who also worked on the guts of the tool.

* The really smart bit of TC was actually put together by a guy called Peter Lamsdale. All I did was take his algorithm - which I still have difficulty understanding much less explaining - and strap a UI around it. An earlier version of TC was published (unofficially) on a website and an article was written about it by Evan Morris. There is even an unconnected MSDN bit of sample code which is nowhere near as effective (IMHO)

In that post he also spells out some more warnings, besides the fact it really does an excellent job of deleting actual emails that are replicated in threaded replies:

... but some obvious potential downsides...

  • The assumption at the top of this post. If I reply to someone's email, but change the contents of their original message in the reply, then TC will retain the modified version and it will look like the originator really said that. There may be ways to work around this limitation now, but I never bothered to figure them out.
  • Legal compliance - maybe you need to keep a copy of every mail for compliance purposes: if so, users programmatically deleting messages could be a *bad thing*.
  • erm, can't think of any/many more...

Outlook Thread Compressor - saved 100MB of redundant e-mail for me! Use with care! - Aaron Tiensivu’s Blog

Thread Compressor for Outlook… works with 2007! – Kurt Shintaku’s Blog.

I can’t wait to get some free-time at work to load thin up on a test machine and feed it a copy of some of my PST files.

I’m planning on testing in on duplicate PST files first to I can get acquainted with it and have a better understanding of it’s operation before I go and feed it my real Outlook PST file.

This rates up there as one of the best software finds of May.

Bonus Outlook tools.

For some additional tools to help you manage Outlook files and contents, don’t forget about all the awesome (and portable) Outlook tools offered recently by Nir Sofer.

Outlook/Office Utilities - (freeware) – NirSoft.

NK2View - (freeware) - Did you know that if you use Outlook the email names used in the To/Cc fields are retained? The NK2 file is the "auto-complete" file. Great place to review if you are auditing an Outlook user's pc. Anyway, this handy utility allows you to view the N2K file, display all the email address records stored, and export them into various file formats. Handy for security techs.  Also allows you to quickly edit, sort, save/restore, and delete items in the file itself.  Particularly useful if you need to bulk-edit the contents due to changes/conversions in corporate address book items.

OutlookAttachView - (freeware) – This utility can help you locate, extract and/or remove attachments embedded in your Outlook email messages.  It displays the list of attached files in your Outlook's mailbox, and allows you to easily select all attachments that you need, and then extract them into a folder that you choose. 

OutlookStatView - (freeware) – Nir is on a roll! For all you Outlook junkies out there, this tool can gather a lot of great statistics on your email habits. Quoting from Nir’s description, “OutlookStatView scans your Outlook mailbox, and display a general statistics about the users that you communicate via emails. For each user/email, the following information is displayed: The number of outgoing messages that you sent to the user (separated by to/cc/bcc), the number of incoming message that the user sent to you, the total size of messages sent by the user, the email client software used by this user, and the time range that you send/received emails with the specified user.”


--Claus V.

1 comment:

Randall Stross said...

Fantastic, Claus. This tool looks like it would definitely save some space on those huge Outlook files.