I know this is an old thread, but in my case it was INSTRUMENTAL in cracking a couple of tough codes.
I had to migrate VMs from PROXMOX onto ESXi 5.0. I did this using VMWare p2v.
What made things work for me:
-Do not use DNS hostnames in the converter, use IP addresses
-Have a helper IP address available for exclusive use by the converter
-The converter does not handle GRUB2, but it will still complete the conversion process otherwise, but it will fail to reconfigure the boot loader and thus not boot
For Debian 8, per another user's reply suggestion in this thread, I used the boot ISO version of https://sourceforge.net/p/boot-repair/home/Home/ . Unfortunately this wasn't enough to resolve all issues.
VMware P2V Conversion: GrubInstaller Error During Conversion of Debian Linux Host | Mantraaz led me to believe that the UUIDs of the drives in /etc/fstab were wrong, which was the case. I used blkid to get the new IDs, updated /etc/fstab with the new IDs, and restarted without issues. One thing of note, if it boots in read-only mode, reboot, edit the boot startup (hit e when it asks if you want to boot Debian) and replace the "ro" flag with "rw".
CentOS 6 (or 5? don't remember) was also a PITA. Unfortunately I got that one converted a month and a half ago and forgot some of the details, but the same general issue of needing to fix the boot loader applies. I believe the following article helped me solve the issues I faced.
TipsAndTricks/CreateNewInitrd - CentOS Wiki
Anyways, thanks everybody who commented in this thread years ago, you helped!