Outlook Thread Compressor download now available

Nearly a year ago, I wrote about Thread Compressor on here – it’s an add-in to Outlook which removes unnecessary emails, on the assumption that most people reply to mail and leave the original intact, so you could keep the last mail in each branch of a thread, and remove all the others.


Way back when I was still developing TC, I tried to get it included on the Office Downloads section of Microsoft.com, but our legal department was (with some justification) very nervous about us offering a download which would go through the end user’s mailbox like a dose of salts, deleting stuff. So it stayed (more or less) an internal tool: I even started developing a “version 5” with a much groovier UI and some extra features.

Included in the v5 beta (which is a real pain to install nowadays – the previous v4.2.030 version has nearly the same feature set and is a lot more self contained), was a piece of logic which captured stats on TC usage and emailed them back to me.

Since many people at MS are still running that beta (it’s a long story, but the source code went south so it’ll never get out of “beta” state), I still get maybe 20-30 statistics mails a day…

Since August 2003 when the first statistics email arrived – from me, kind-of naturally – until 24th April 2007 (when I last did an analysis of the stats), TC v5 beta had scanned over 400m email messsages and had compressed over 30m, worth nearly half a terabyte of email data.

To the reader, the spoils

Well, I finally decided – in an “ask forgiveness rather than permission” move – to make the last complete and stable version available for download.


It’s not particularly elegant looking by modern standards (given that most of it was written 7 years ago in VB6) but it does work, even on Windows 7 (x86 and x64) and Office 2007. Basically, anything post-Office 2000/Windows 2000 should be OK.

A reader called Mark Ruggles emailed me the other day and said:

“It is fantastic and it works like a champ in Outlook 2007. I turned it loose on my Inbox and my archive and I deleted 103Mb of redundant data. I sent it out to some of my colleagues and my manager used it cutting his archives down by 2Gb.

This is the coolest utility I’ve found in a long time.”

So, thanks to Mark's comment, I’ve now registered www.threadcompressor.co.uk and posted install instructions and a download file up there.

Comments (9)
  1. Anonymous says:

    Ewan has finally gone ahead and posted this amazing tool externally .  Thousands of us have been

  2. prabhupr70 says:

    Will this run on archive PST file?

  3. EwanD says:

    Yes, it will run on PST files as well as Exchange mailboxes.

  4. Anonymous says:

    This tool originally was a long fabled internal Microsoft tool that finally has a somewhat proper "official" release to the web with plenty of warnings and caveats. It is an add-in for Outlook 2000/XP/2003/2007 which removes unnecessary emails, on the

  5. EwanD says:

    @Phillip Remaker… I think it’s going to take a bit more than the way messages are displayed to act as a clarion call for messaging architects to dump Exchange in favour of GMail.

    As it happens, Exchange & Outlook are both evolving the way threads are handled – but preserving the original messages as well as being able to show a summarised view. Keep an eye on Exchange/Office 2010 for more details if you’re interested.

  6. John Gilham says:

    Thank you for releasing this great tool!

  7. Phillip Remaker says:

    This just points out  the fact that current Outlook and Exchange model for message storage and presentation is inappropriate for modern email usage.  GMail already threads conversations and compresses out redundancies in the presentation while completely preserving timestamp and header information.  GMail also does not face the "top-post" assumption inherent in thread compressor.

    While this helps hide the deficiency of native Outlook, it should really serve as a broader call to action to the Microsoft Messaging architects.

  8. Anonymous says:

    Would you have any plans of possibly making an Outlook 365/2017 compatible version? I would pay money for that!

  9. Looks like the site’s down.

Comments are closed.

Skip to main content