An MSDE database is limited in total size to 2 GB. How quickly you reach 2 GB depends on the number of members you have, the frequency with which you send, how long you keep archives, incoming mail and outgoing mail, and other factors. If you are upgrading from 4.x or lower, and wish to use MSDE, you can determine how large your total database size is by adding together the size of all the files in your db directory.
ListManager will warn you via email if your database is growing too large. If you are running ListManager in the foreground and your database is too large, you'll see a message similar to this one:
severity: 17 - Insufficient Resources - The statement caused SQL Server to run out of resources (such
as locks or disk space for the database) or to exceed some limit set by the system administrator.
msgtext: Could not allocate space for object 'members_' in database 'ListManager' because the 'PRIMARY'
filegroup is full.
If you find that your database is growing too large under MSDE and are unable to trim its size by managing the length of time data is kept, you should consider upgrading to a stand-alone SQL server.