Customising Exchange Warning Messages

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I was recently asked by a customer to find out if they could customise the default system message generated when users reach their mailbox size limit. This message recommends that the user sets up a PST file to archive old messages. The site policy is not to allow PST files, so the quota message had to be changed to reflect this. While this isn't a supported change, many customers require it, so here's how.

 

To do this we can use the RLTOOLS to change the MDBSZ.dll file. This change is not supported so if in the future you have some issues around this dll you must rollback this change. It's important to note that if in the future any service pack or any hotfix updates this file (MDBSZ.dll), it will return back to default settings.

Before you make any changes please backup MDBSZ.dll. If you're operating an Exchange cluster you will have to update the file on all nodes. Also, if possible test the changes on a non-production system first.

Download the file rltools.exe from ftp://ftp.microsoft.com/softlib/mslfiles/rltools.exe

 

Once you download this file, create a folder called RLTOOLS on the desktop and copy RLTOOLS.EXE into that folder. Double click RLTOOLS.EXE and a command window will open and a bunch of files will be extracted and placed in the RLTOOLS folder. One of the files is called RLQUIKED.EXE. This is the editor that allows us to edit DLL file.

The file we need to edit is called MDBSZ.DLL. This DLL file stores the various strings that are displayed as a part of various error/warning messages.
Start the tool RLQUIKED.EXE

  • Click File, Open and change the files of type selection to DLL.
  • Point to C:\Program Files\Exchsrvr\Bin (or you Exchange install location) and choose the MDBSZ.DLL file. I am assuming that Exchange is installed on the C Drive. 
  • Click Open.
  • Double click the line that starts with "To make more space available......"
  • In the Message Text window, make the change you desire and click OK.
  • Click File and Save As and choose MDBSZ.DLL.
  • This may fail if the Exchange Services are running. So, do this with the Exchange Services stopped if possible.
  • Finally, test the change by setting quota limits on a user object in AD.