device: 0.824 architecture: 0.692 vnc: 0.626 performance: 0.497 files: 0.458 boot: 0.437 semantic: 0.427 risc-v: 0.421 register: 0.394 VMM: 0.377 socket: 0.350 mistranslation: 0.335 TCG: 0.315 graphic: 0.313 ppc: 0.309 PID: 0.275 kernel: 0.258 debug: 0.185 permissions: 0.137 i386: 0.130 arm: 0.129 user-level: 0.111 assembly: 0.090 x86: 0.078 virtual: 0.074 network: 0.066 peripherals: 0.038 KVM: 0.035 hypervisor: 0.012 scsi disk emulation doesn't enforce FUA (Force Unit Access) in write-back mode Microsoft NTFS utilizes the FUA bit in SCSI WRITE CDBs to insure integrity when a device advertises that it has write caching enabled. The FUA bit is meant to ensure a write is written to non-volatile storage before returning. This seems to not be enforced by QEMU's SCSI emulation code. Can you still reproduce this problem with the latest version of QEMU? Closing since there hasn't been any response within the last 7 months Fixed in 1.1 (commit 7e8c49c56154ab5c45d4f07edf0c22728735da35). :)