So I mistakenly allowed 10.13.5 install on a machine which looks to have corrupted the partition map. Diskwarrior - I may consider, but right now it can't rebuild APSF 10.13, until they are able to get full documentation from Apple, accoring to their website, the next release will have that functionality. I tried iBoysoft but that crashed while reading the drive. Not a ringing endorsement. What other options are there or is it watch and wait for Diskwarrior? Thanks in advance for advice and help as always!