Those VMs tend to be modified specifically for the applications and include boot dependencies that are encountered after a recovery operation.
In the absence of this CDROM, WebSeal’s boot fails, and recovering this machine will always result in a failed to boot recovered VM because Zerto Virtual Replication, does not support attached devices, such as CD-ROM and USB.
If the VM protected by Zerto Virtual Replication has a boot dependency for devices such as CD-ROM, Zerto recommends writing a post-script that, post recovery, will attach the device to the machine. For example, in the case of WebSeal, write a post-script that, post recovery, attaches an empty IDE CD-ROM device.
For more information regarding running pre- and post-recovery scripts, refer to Running Scripts Before or After Recovering a VPG in the Zerto Virtual Replication documentation.