There was an internal cast of (int) for the email quota limit number, so if you get 4096M, which is 4294967296 in bytes, which is too large for an int, it caused a size check error. There is a check for: if (qlimit/(1024*1024) == 0) which is looking to see if the size in meg is less than 1, and that's when it adds decimal points. The cast caued this division to be incorrect, showing 4096.000.