When hardware resources are shared between mutually distrustful tenants in the cloud, it may cause information leakage and bring difficulties to regulatory control. To address these concerns, cloud providers are starting to offer hardware resources dedicated to a single user. Cloud users have to pay more for such dedicated tenancy; however, they may not be able to detect the unexpected misuse of their dedicated storage due to the abstraction layer of the cloud. In this paper, we propose TerraCheck to help cloud users verify if their dedicated storage devices have been misused to store other users’ data. TerraCheck detects the malicious occupation of the dedicated device by monitoring the change of the shadow data that are residual bits intentionally left on the disk and are invisible by the file system. When the cloud providers share the dedicated disk with other users, such misuses can be detected since the shadow data will be overwritten and become irretrievable. We describe the theoretical framework of TerraCheck and show experimentally that TerraCheck works well in practice.