High Sierra Instal: What does "failed to write file " mean

I am trying to install High Sierra on a 27", Late 2012 iMac. I've been in recovery mode, used disk utility to repair the startup disk, and done everything else I can think of to solve the issue. Every time, the installation is progressing fine until I get an error message that the installation is terminated. The error log always comes up and says "opendirectory [183]: Auth Failed to write file <Private>.

I don't know what this means and don't know what to do to correct this.

I would appreciate any help... Thanks.