We have seen cases where the OpenVMS 7.3 installation from an ISO image goes into a mount verify and does not recover when run from an emulated RRD42.  If this problem is encountered, ensure the emulated CD drive advanced properties are set as follows:

•vendor:                DEC

•model_num:        RRD40

These setting eliminate the problem.  The VMS 7.3 device driver seems to have issues with the RRD42 device.