Target Disk Mode Permission Problems - Workaround. SOLVED

Source iMac: macOS Mojave – 10.14 - failed HD, and my Time Machine backup also failed. Username: ctfuqua

Target Macbook Air: macOS Catalina – 10.15. Username: CToddCreations

We did all the normal troubleshooting. No hardware diagnostic errors. Did disk repair in recovery mode, and no errors on the source machine. But, the iMac wouldn't boot up. It hung on the process bar. Wasn't able to boot into Safe Mode. Unfortunately my Time Machine backups had stopped running, so I had a months worth of critical files that weren't backed up. So, wanted to use Target Disk Mode to selectively copy the files over from the failed iMac. NOTE: have to use a Thunderbolt cable; USB-C cable will NOT work.

Was able to connect the Target MacBook to the Source iMac in Target Disk Mode, and could see all my files. But, most of the user folders under the User were restricted - Photos, Movies, Documents. They have a no access symbol and if I attempted to access them I get a message that you do not have sufficient permissions or something similar. There are other posts about this answer, but no real good solutions we could find. Note: I did not use file encryption or other third party security apps; I just have a username with a login password, standard Apple best practice.

I worked with Apple Support, and the first solution that seemed to possibly work was to copy the entire user folder over. Then, we expected we could fix the permissions on the target machine. But, there was 2.5TB of files and that would take forever. But, at least we were able to start the copy. Looking at other solutions, this seemed to be the best route.

Then, we looked at the Info/Permissions for the User folder on the Source machine. It looked like there was sufficient read write access for the target machine username ctoddcreations. We added a NEW user of ctfuqua, which matched the user name of the directory on the Source machine. We added it with Read/Write privileges and voila - the folder was accessible. I could copy individual folders or files. I don't now if the username HAS to match. For what it's worth, I also added access rights for Administrators, and set this to Read/Write privileges and that did the trick as well.

Image 1: Target machines view into the Target Drive mode for the Source machine. Permissions locked.

Image 2: Using Command-I, we added additional users with R/W privileges to the Pictures folder in this case, and it removed the restricted access.

Image 3 - the pictures folder after the new permissions