Are you the one like me who suddenly sees the Hard Disk space slowly running out more importantly going unaccounted? Do you have one or more applications that are recently crashing quite regularly then that could be the culprit. This could happen on a Windows 2003 Server or a Windows XP PC.
This happens when Windows Error Reporting is enabled on your Windows 2003 or Windows XP system. Windows Error Reporting dumps the memory into two dump files everytime an application crashes. One is a HDMP file which is an uncompressed version of the memory dump while the other is a MDMP file which is a compressed version of the memory dump file which will be sent to microsoft if you choose to.