Outlook 2003 - Junk Email List error in conjunction with Exchange Server 2003

Posted on 2004-12-01
Last Modified: 2012-06-27
We have a client that has outlook 2003 conected to exchange 2003.  They are reciving the following error:

"Unable to add to the server Junk E-Mail Lists, you are over the size allowed on the server.  The Junk E-mail Filter on the server will be disabled until your Junk E-mail Lists have been reduced to the size allowed on the server."

I am wondering where this setting on the server is and if there is a way to change it.  How can I prevent this error from happening again?

Is this an error being generated by Outlook 2003 or the Exchange Server
Question by:brownmattc
    LVL 49

    Expert Comment

    Not sure if you can reduce the size but check this

    I am receiving a server size limit error message when I try to add a name to my Junk E-mail Lists.

    When the size limit for the Junk E-mail Lists is exceeded on the Microsoft Exchange server, the lists are not available from any computer (also known as "roaming") and are used to evaluate messages only on the computer where the lists are stored.

    There are too many names or e-mail addresses on one or more of your Junk E-mail Lists. Review the names on each of the three lists, and then delete some of the names.
    Make the Safe Senders List shorter by excluding your contacts from this list. On the Safe Senders tab, clear the Also trust e-mail from my Contacts check box.
    There are too many contacts in your Contacts folder. Switch to Contacts, and then determine whether there are any contacts you can delete, or create a separate contacts folder and move some contacts to the new folder.

    Source :
    LVL 21

    Expert Comment

    Just to clarify, the user is accessing an Exchange 2003 mailbox using the Outlook 2003 client desktop application, as compared to accessing the same mailbox using Outlook Web Access 2003 version?  

    This error looks more like an OWA error than an Outlook error (specifically this one "An error occurred processing your junk e-mail lists.  You are over the size limit allowed on your server.  Contact your server administrator.")

    OWA has a max of 1024 entries which cannot be increased.  There isn't any limit that I am aware of in the Outlook 2003 client itself, if there is one is is SIGNIFICANTLY higher than that.  Here is an update to the Outlook 2003 junk email:

    As for the Exchange server, by default you have a 512kb cumulative limit on the combined total size of the junk e-mail lists (Blocked Senders, Safe Senders, Safe Recipients, Blocked Encodings, Blocked Top-Level Domains)

    You might have hit the 512 KB limit, if so the workaround is to increase the limit via the following registry key on the Exchange 2003 server.

    Value: Max Extended Rule Size
    Type: DWORD
    Data: maximum size, in bytes, you want to allow for the junk e-mail rule
    LVL 4

    Author Comment


    Traval - Thanks for the info.  Is there a microsoft KB articale that you got the workaround from or some other source?  I assume that if I increase the size (to say 2048) that the users could then filter 3 times the amount of addresses...Is that correct?

    The user recived this message when they first launched Outllook 2003 on their desktop.  Users have the option of using OWA but in most cases they use their Outlook 2003 client on their desktop.

    Are you saying that a user can only filter 1024 email address in OWA (but potentailly many more if on their Outlook 2003 desktop client)?  Is that junk list stored on the server or on the client (if they check email from another computer is it still filtered using there junk list?)?

    Thank you for all your help,


    LVL 21

    Accepted Solution

    I don't think there's a KB article, but here's something from TechNet:

    Although it says 510kb, I thought it was 512kb.  No biggie either way.  Here is some more info from that guide:

    Setting the Size of Spam Rules
    The spam rule on a user's Inbox includes the user's safe senders list, blocked senders list, and Outlook metadata of about 300 bytes. By default, the size limit for a user's rule is 510 KB. This default size typically allows for about 2,000 entries in the safe senders and blocked senders lists.

    Because the safe senders and blocked senders lists are synchronized between Outlook clients and the mailbox store, large lists can affect performance. You may choose to reduce the size limit. Conversely, you may choose to increase the size limit to allow users more flexibility in configuring the safe senders and blocked senders lists.

    You can set a custom size limit for these rules by adding a new registry key value to the following registry key:


    Note :
    You must enter the new size limit in bytes when using this registry key.
    To customize the size limit of a user's spam rule
    1.  In Registry Editor (regedit), in the details pane, right-click System, click New, and then click DWORD value.
    2.  Type Max Extended Rule Size for the registry key value.
    3.  In Edit DWORD, under Value Data, enter the maximum size in bytes you want to allow for a user's spam rule.

    OWA can only use portions of the junk mail filtering, all of it done by the client.  An Outlook client connecting to the same mailbox can filter out a lot more of the junk than accessing thru an OWA session can.  Some of the functionality is performed by the server and some can be performed on the local machine.
    LVL 4

    Author Comment

    Thank You,

    We fixed this problem by deleting and recreating the Outlook Profile.  Now there is no message.  I susspect that it has something to do with us recently migrating from Exchange 2000 to 2003 and something being leftover in the profile that was pointing to the old machine.

    I have given Traval the points because he was able to find out how to increase the limit on the spam filter.

    Thanks Again,


    Expert Comment

    I tried the suggestion detailed above and in the article and now we get the message every few minutes instead of just when we open Outlook.  Basically the fix applied made the problem worse.  I attached a screen shot.


    Expert Comment

    I am also having this problem, all the junk email stuff is empty and turned off and the error still pops up, the registry key is changed to 10000KB and the error is still popping up on 4 clients, both 2003 and 2007 outlook and exchange 2003 server.

    Expert Comment

    I am also having the same issue RDComputers is experiencing. I ran the Exchange Console command, which seemed to have fixed the problem. People were also getting a limitation of rules error, but after running that command that seemed to have fixed the problem and the Junk error.

    This is the command I am referring to was found here:

    When running the command I received this message:
    WARNING: The command completed successfully but no settings of 'domain/Users - Custom/Users - Resources/user' have been modified.

    I do not know if there is a correlation between rules and junk, but it seemed to have "fixed" the problem. At least, temporarily.

    I tried inserting the new reg key, but as RDComputers is experiencing, I also had the message pop-up non-stop. I had to remove it to slow down the amount of pop ups.

    As for right now, we have no resolution and users (myself included) are still getting the Junk error.
    Get-Mailbox | Set-Mailbox -RulesQuota 256KB

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