Diskeeper works safely and effectively with email servers, whether they are Microsoft, Exchange, Lotus, Domino, QUALCOMM, Eudora, or others. Diskeeper is uniquely designed to run in the background while these applications are operational and available to users. There is no need to stop or shutdown these applications or services to defragment. There are two types of volume-centric fragmentation with which Diskeeper is immediately concerned: file fragmentation and free space fragmentation. File fragmentation concerns computer files that are not contiguous, but rather are broken into scattered parts. Free space fragmentation describes a condition in which unused space on a disk is scattered into many small parts rather than a small number of larger spaces. File fragmentation causes problems with accessing data stored in computer files, while free space fragmentation causes problems creating new data files or extending (adding to) old ones.