SMF was written with hard-coded limits on some of the things stored in the database. These were set based on assumptions about typical database and webserver capabilities as well as some assumptions about typical forum communities. If your forum is much bigger than usual, you may increase these hard-coded limits. When you do that, you should be aware that you may need to investigate optimizing operations involving the quantities you are now increasing beyond what the developers planned for. Enjoy!

• Attachment -- 4,294,967,296
• Category -- 255
• Events (Calendar) -- 65,535
• Members -- 16,777,215
• Posts (all Topics and replies) -- 4,294,967,296
• Themes -- 256 installed. You may have trouble administering Themes and Layout with more than 100 themes installed.