This by far is the easiest and best solution here.
It automatically takes all the files and future files by a user created by Outlook and directs Outlook to find them in the specified directory.
Not only is it easy - but it just works without issues. Furthermore, if you ever have to reinstall windows - one registry entry after re-adding your accounts and your done. The registry entry to export all your account information for Outlook available on other websites. As such - if you need to restore your system drive - its simply a few registry additions from an exported branch of the registry tree, the change of this registry entry, and entering the passwords for the accounts and your all set.
It is by far also the best solution because it forces all of the pst, ost, nst etc files to be on the data drive and with all the SSDs on the market - you surely DONT want your email on your SSD drive eating away at it as they only have so many IOPS before death. In all honesty you probably will never reach that with or without this change - but I rather reduce as many reads/writes on my SSD as I can.
I am a firm believer that users should put on a separate drive all user data and preferences (as much as possible) and keep the OS drive as pure as it can be with only OS and applications and limited preferences/data on it. As such, any user data should be on a data drive. The industry built around Microsoft is slow to embrace this (Google and others have already as has the Unix world decades ago). But there is hope as the SSDs are pushing for this change just because of their nature.
Microsoft really needs to wake up though and make changes to Windows 8 that will encourage and enable application developers and users to have a pure data drive for everything from documents, photos and images to email and movies, and even user preferences for the OS and applications.
We need to evolve beyond the registry for storing all user's preferences on apps - where the registry slowly gets corrupted over time. There is no reason that the bulk of the data that Microsoft / Application developers push on people should be on the OS drive without an easy way to select a data drive. In fact there are a myriad of reasons why NOT to do this (eg just one being to have two types of backups for your system - the system drive and the data drive, with difference backup frequencies.)
Anyway - this is the easiest way to make one change and have it affect any and all mail accounts I create in the future under my account (except for what I posted below in a later edit). Any other way directs you to make changes every time you might add or change a mail account. Not smart or easy.
The only easier thing would be to be able to propagate this for all users. I dont see how that could be possible under you make this change for every user added to your system. I suspect there are programs/tools that will do this (e.g. every time a user is added a script is run and taking account of where Outlook puts its data directory - to make this change to the registry). I am not up to date on my tools as to which would be best for this - but I am sure it is most likely possible and frequently done by system administrators (which I am not). Any experts care to add this?
I have a need for doing not only this for the Outlook directory - but for moving automatically for any new user added all the directories possible under the %systemdrive\users\%username that contain user created data or user created preferences.
Application developers need to pay attention to this too - such as Steampowered who sells games to so many individuals - but after you install their program on C - they force you then to install every application that you buy from them on the C drive as well (e.g. the system drive). When you have expensive SSD running your OS - you damn sure down want every game you buy to be on the system drive. The fix is to install Steampowered app onto the data drive initially - which then forces all games bought from them to be installed there - you need to however, do it intelligently - so I mimicked C:\Program Files (x86) to be on the data drive.
I did the same with many of the /users/username/appdata paths such as those I could for programs such as Trillian, Research in Motion's Blackberry, PopPeeper, Microsoft Livemail, etc. as well as a special directory for Email downloaded by Outlook (now forced to be in that directory thanks to Peter.)
NICE find Peter. (By the way Peter where did you find this registry entry? I want that list and the source to that list - Im sure I could find many other useful entries). I would vote your entry up but I am a new user. The only issue is hotmail/live etc accounts that use the Outlook Connector as this registry change didnt affect that (of course).
I did find this registry entry also for Exchange and thought it might work on Outlook Connector - but (of course?) didnt despite that Outlook Connector writes an OST file: Value name: ForceOSTPath
I found it on MsOutlook.Info site on this page which then also showed me the following (thus demonstrating Microsoft's incompetence and apathy towards users, their needs, and trends in technology over the last decade):
Using IMAP and the Outlook Connector
Adding these registry keys will not
affect the default location for newly
created pst- and ost-files for IMAP
and Outlook Connector accounts. There
are currently no reliable methods to
change the location of the storage
files for those accounts and it is
recommended to leave them in the
existing location. Note: Do not set
the path to a network location as this
is not supported nor recommended by
Microsoft as it could lead to slow
performance, data corruption or even
So unfortunately - no one can use Outlook Connector for any email account at Microsoft and put their data store where they desire. Personally, I'm screwed because I cant place it on a different drive other than my SSD drive (system drive). I would be curious to see any hacks for forcing Outlook Connector to use a different drive - but right now Microsoft is just so many years behind in support the separation of OS and APPs from user data - which is why they are also a decade behind or more in developing solutions for the cloud that rely on this concept.
Since I don't like being screwed by big companies, the only logical decision is not to use Outlook Connector at all, thus not use Hotmail or Live or any of their products that push data onto the system drive this way. So I have forwarded all of the mail that comes in for Hotmail to my Gmail account and Gmail can allow you to respond to the Hotmail emails as if they were from Hotmail.
So basically my ancient Hotmail email address can live on but I abandon Microsoft's handling of it - which really is where most of my computing is heading. I may have to keep the OS for now since everything is made for it, but my goal is to reduce the usage of every part of it that I can, and that makes sense to abandon technologically and budget wise.
However, back to Peter's original find (which is also on the MSOutlook.info site): this registry entry will be with me until Microsoft wakes up and makes it so ALL user data can be on a data drive. Otherwise, I will be forced to leave MS Office and Outlook completely behind. Sun's Office is looking pretty good right now.
(IMHO Sometimes Microsoft technology is about 10 years behind common sense and other company's technology e.g. Bing vs Google. Most all of Microsoft's great talent is either retired via stock options or went to Google or other companies. Ballmer sure isn't getting the job done.)
Now to make changes to my registry.
0 down vote Hi,
You can only change the location in
the registry ...
Close Outlook Create a folder where
you want to put the IMAP datafile Copy
the PST file with the name of your
IMAP profile from
to the desired location (eg the new
created folder) Afterwards, Click
Start / Run and type "Regedit" (You'll
need administrator rights for this) Go
Add a REG_EXPAND_SZ (Expandable String
Value) with the name: ForcePSTPath
Fill in your new folder Start Outlook