There are several reasons why a virtual machine might take up more storage space than expected: The VM has one or more snapshots. When an image is taken, a copy of the VM's memory state (called a delta disk) is created in addition to the standard VM files. The delta disk grows more prominent each time another snapshot is taken until it reaches the size of the original VM disk. When an image is deleted, the delta disk is deleted as well. To learn more about snapshots and how they work, see Understanding snapshots in Hyper-V. The VM is configured to use one or more fixed-size virtual hard disks. Fixed-size disks occupy their total allocated size on disk, even if they don't contain that much data. For example, if you create a 500 GB fixed disk but only store 50 GB of data, the file containing the disk will still take up to 500 GB on your host system's storage drive(s). If possible, we recommend using dynamically expanding disks instead of fixed disks. Dynamically developing disks only occupy as much storage space as they need at any given time, so they're more efficient in terms of storage utilization. To learn more about dynamically expanding and fixed disks and when to use each type, see Understanding differencing disks in Hyper-V.