Solaris Common Messages and Troubleshooting Guide

setmnt: Cannot open /etc/mnttab for writing

Cause

The system is having problems writing to /etc/mnttab. The file system containing /etc might be mounted read-only, or not mounted at all.

Action

Check that this file exists and is writable by root. If so, ensure that the /etc file system has been mounted, and is mounted read-write, rather than read-only.