diff --git a/sys/dev/raid/hptmv/ioctl.c b/sys/dev/raid/hptmv/ioctl.c
--- a/sys/dev/raid/hptmv/ioctl.c
+++ b/sys/dev/raid/hptmv/ioctl.c
@@ -691,7 +691,11 @@
 hpt_rebuild_data_block(IAL_ADAPTER_T *pAdapter, PVDevice pArray, UCHAR flags)
 {
 	DWORD timeout = 0;
-    ULONG capacity = pArray->VDeviceCapacity / (pArray->u.array.bArnMember-1);
+    ULONG capacity;
+
+	if (pArray->u.array.bArnMember <= 1)
+		return;
+	capacity = pArray->VDeviceCapacity / (pArray->u.array.bArnMember-1);
     PCommand pCmd;
 	UINT result;
 	int needsync=0, retry=0, needdelete=0;