What is the problem with machine images when it comes to migrations?

The machine image approach: When an entire image is moved, all of the infrastructure elements come with it, including: security systems, backup, monitoring, management and so on.  This all inclusive aspect may not be appropriate for a new environment.  It's not just device drivers that need to be changed. Differing configuration surrounding a machine will also cause migration problems.  For example, if multiple network segments are in use, or if new storage configurations are required, adjustments must all be made for each instance at the OS level.  With AppZero, these aspects can be set up as required in a standard way and the virtualized mount points and networking can simply be set to use the existing configuration.