2019-03-04T11:39:09.840Z info vmware-converter-helper[F2EB3B70] [Originator@6876 sub=task-1] KeepOneBootEntry: Commented out line: : # (removed by Converter) menuentry....
As noted in the above quote from the helper log file, Converter comments out lines from grub.cfg like this:
: # (removed by Converter)
while the correct way would be:
# (removed by Converter)
This mistake (an extra colon in the beginning of the line) causes the first boot to display unnecessary warnings and increases the need to remove old kernels from the source to reduce the warnings in the target.
The 'mistake' has been done on purpose. There are other cases when the destination VM is unable to boot w/o the colon (GRUB's bash treats if/else statements w/o command after 'if' as syntax error). The current situation is the lesser evil. We will think of a better solution for future releases.