Microsoft Exchange and Remote Desktop Services Specialists


Microsoft Exchange Server and
Blackberry Enterprise Server news, views and fixes.

Mailbox Limits

There has been some chatter in a number of forums on setting mailbox limits. 

  • How big they should be 
  • Should they be used at all 
  • Good practise to work with limits.

One of the first questions people ask is whether there is anything official from Microsoft on limits of mailboxes. At the time of writing there are only broad recommendations. 
That would be like a car manufacturer telling you how fast you can drive your car. The only limit is its top speed (the size of the Exchange database).
Setting mailbox limits depends on many factors, and the sizes used are different for every company. You may need to have different limits for different people.
When deciding on the limits, some of the factors you need to consider are:

  • number of users 
  • number of servers 
  • amount of disk space 
  • regulatory or legal requirements 
  • types of messages being sent.

A 100mb limit might be good for sales people, but marketing or designers who often move around large files might require a larger limit.
You may also need to have larger limits for VIPs, who will often demand the larger limit "because they can".
In all cases, the maximum limit you can set though the GUI is 2gb. If you want mailboxes to go larger than that then you have to use adsiedit.msc. If you don't have access to that tool, they will have to be unlimited. 

Mailbox Limits Good Practises
When I deploy limits I always limit down, not open up. The global limit is the largest that anyone can have (is effectively the default) and then users or groups are limited down from that point. It provides a simple safety net in the case of a problem.
Even if the client isn't using limits, I will often set a global soft limit of 1gb, which puts a check in place in case any mailboxes get out of control. If the mailboxes are small, then it can be set to a hard limit.

Managing Limits
The easiest way to manage limits is to use separate storage groups and databases. This is only available in Exchange Server Enterprise edition. Try to avoid setting limits on individual mailboxes as this increases the administration of the system.
If you are on Exchange standard edition or SBS and want to vary the mailbox limits, you will need to set them on each mailbox. Use a tool like to set the limits in bulk.
Remember to limit down rather than open up.

Hard and Soft Limits
I have already mentioned these two types of limits.
A hard limit stops the user from doing anything with the mailbox until they have removed some content.
A soft limit simply sends tem messages saying that they are over the limit.

Mailbox Limits Drawbacks
Mailbox limits will not solve a email storage problem.
If you place limits on mailboxes then you will always have the "pack rats" who want to keep everything. They will then move their email to PST files, which are even worse.
An email message stored in a PST file will use up to three times the space the messages does within the message store.
You will also loose single instance storage, which could further increase the size of the PST file. Consider this - if you send a 5mb attachment by email to 10 people, then it takes up 5mb in the Exchange server due to single instance storage. It will use at least 50mb when stored in PST files.
Then there are problems with backing up the data - a PST file is very difficult to backup. It shouldn't be stored on the network, and if the file is open in Outlook, then it will be locked.
Alternatives to Mailbox Limits?
If you want to limit the amount of email that users store in their live mailbox, but don't want them to use PST files, you need to look at deploying an additional application.
An ideal tool would be a journaling application such as GFI Mail Archiver. This stores a copy of every email that passes through your server and stores it in an SQL database. Users can then get access to those messages and get a copy sent to them so that they have it in Outlook.

Archiving Email
The term archiving is being used by the software industry to refer to two very different practises. You need to understand those differences, then select a product that meets your needs. 

  • True Archive Product.
    This is an application that sits in the background on your Exchange server and extracts automatically old content and stores it elsewhere. A tag is left behind in the mailbox that points to the alternative location. As far as the user is concerned, this is transparent.
    This type of product is no good for regulatory use, as it still allows the user to tamper with the email message. 
  • Journaling Product.
    This is a product that takes a copy of every message as it passes through the server. It does not touch the mailboxes in any way. Users need to manually manage their mailbox content, confident that they can get a copy of any message back from the database.
    Ideal for regulatory use as it stores a message is SQL which can show when the item was last modified.

Windows Mobile Emulator Released, with MSFP Images

Microsoft have released the Windows Mobile emulator as a finished product. It was a Public Preview in the past.

Along with the emulator itself, they have also released images for Windows Mobile 5.0 containing the MSFP firmware upgrade, so you can now test almost all features for yourself. The one feature that doesn't work is the push technology, as this requires a mobile phone connection. However all other aspects work as they do on a full installation.

Download links are below.

One point to note - unless you have Virtual Server or Virtual PC installed on the machine, you will need to install the VPC driver (link also below). However after installing this driver it is not enabled. You have to go in to the properties of your Ethernet card and enable the option.

The application still has a problem if you have a regular Windows Mobile device connected at the same time as you start the emulator, so make sure that it is disconnected before starting if you want the emulator to see your network.

Download Links.

Emulator Installation and MSFP images

Virtual Machine Network Driver

Windows Mobile 2003 Second Edition Emulator Images (Required validation)

Related Links @
Windows Mobile 5.0 Emulator:
SSL Certificates on Windows Mobile:

Emulator with MSFP/AKU 2.0

The Windows Mobile 5.0 Emulator preview is an invaluable tool if you have to support Windows Mobile 5.0 devices. However, to date, (April 2006), the only image that has been released with the latest software has been a landscape Smartphone (see here: Smartphones don't make very good emulators, and their functionality is very limiting compared to a full Windows Mobile device. 

However, one of their OEMs has released an image, but this is a little more difficult to get hold of. Not only that, but the image is for one of the most popular Windows Mobile devices in the USA.

The PALM Treo 700w.

Getting the Image

There is a little more effort required to get the emulator files for the Palm Treo 700w as it it is tucked away inside their developer programme.

Therefore you need to join their developer programme, which is free of charge. It requires a working email address as they send you the login information by email.

Once you have become a member, go to the Treo 700W page and download the 26mb zip file. After unzipping the file, you will find a single MSI.

Unfortunately, like the SDK from Microsoft, this MSI requires the presence of Visual Studio to install.
This isn't a major problem. As you may have read on my web site, I have a technique to break in to the MSI file and extract the files that you need.

Once you have extracted the contents, get the bin file from the folder "0409" and the skins file from the folder Treo700w1-10 (should be an XML and some image files). Put them in the same folder, somewhere easy to remember as you need to enter the path in to a command line.

Using the Image

Once again, it requires a command line start of the Emulator. Here is a sample, where the bin file and the skins have both been dumped in to the same folder, called 1, in the root of the C: drive:

C:\>"C:\Program Files\Microsoft\Device Emulator Preview\DeviceEmulator.exe" "C:\
1\nk.bin" /skin "C:\1\Treo700w.xml" /p /memsize 256 /s "C:\Program Files\Microsoft\
Device Emulator Preview\treo700w.dess"

Command lines as my previous blog posting, but in case you are reading this standalone:

/skin is the location of the XML file. Enclose in " if the path contains spaces.
/p enables the NE2000 network card
/memsize is the amount of RAM allocated to the device. 256 is the max
/s is the place to save the image

All other options outlined on my web page at apply to the image as well.

Notes and Observations

Make sure that you give it more than 64mb of RAM, as per my command line above. Less than that and everything doesn't load correctly.

It appears that the actual push functionality doesn't work, which is not surprising as push only works over a mobile phone connection, which the emulator doesn't have. All other functions work correctly.

I was able to get SSL certificates installed on the device, so if you need to import one then this shouldn't be too difficult. Use the Storage Card trick (on the page at linked above).

E12 (aka Exchange 2007)

One last word - this image works wonderfully with E12. On my Beta system it connected straight away, did the online lookup to the GAL and basically everything worked as it should.

Update for Exchange 2003 on

There is an important update on the Microsoft download site for users of Exchange 2003. It deals with a change in the operation of Internet Explorer following a patent case.
The knowledgebase article is here:
The download is here:

Page Editor and 8 Million Points at Experts Exchange

I still remain very active on Experts Exchange, fitting it in with client work. Very handy thing to do while wait for an OS or application to install, server to reboot, or mailboxes to move.
During the weekend I also became a page editor for the Exchange Server topic area, and in the last few minutes I have just hit the landmark level of 8 million points.