diff --git a/src/Driver/Ntdriver.c b/src/Driver/Ntdriver.c
index 402301c3..2b0c0355 100644
--- a/src/Driver/Ntdriver.c
+++ b/src/Driver/Ntdriver.c
@@ -752,7 +752,7 @@ NTSTATUS ProcessVolumeDeviceControlIrp (PDEVICE_OBJECT DeviceObject, PEXTENSION
 				&ullNewOffset);
 			if (hResult != S_OK)
 				Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
-			else if (S_OK != ULongLongAdd(ullNewOffset, (ULONGLONG) pVerifyInformation->Length, &ullEndOffset))
+			else if (S_OK != ULongLongAdd(ullStartingOffset, (ULONGLONG) pVerifyInformation->Length, &ullEndOffset))
 				Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
 			else if (ullEndOffset > (ULONGLONG) Extension->DiskLength)
 				Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;