Bless tool was unable to set the current host disk

[Paulimmanuel]

thanks in advance...


i have two HD in my 2012 MacBook Pro, one (slave) is with macos 10.12.6. The other is my actual boot disk with 10.13.3.

i needed my old email to start up to retrieve an important mail, so went back to boot my old disk, no problems so far. (I know, could be done differently, but caused me problems)

Now, wanting to startup my master disk again, i selected this disk in ‘startup’, and i got the info:
‘Bless tool was unable to set the current host disk‘.

i tried to startup holding the option key and then select the disk....to no avail. It keeps starting up the old disk...

Info: my new disk is ssd and i can still get to all my data on that disk...

HELP!!

 

[Cory Cooper]

Hello and welcome.

Sorry for the delayed response.

Sounds like it may be related to APFS in High Sierra.

-Is the macOS High Sierra 10.13.3 SSD the main drive in the standard hard drive slot?
-Is the macOS Sierra 10.12.6 "slave" drive installed in the optical drive bay with an adapter?
-If the above is correct, did the macOS High Sierra SSD main drive get converted to APFS instead of HFS+?

C