I copied 6.0rc11 on a RB750 which already had 6.0rc11 and rebooted, after the boot completed ssh wasn't working (connection refused, "/tools ssh" missing). Also resetting the configuration to the default one leaded to failures and ultimately the ethernet ports became all disabled. I had to netinstall the box to recover it.

Also tried with 5.24 without such issues.

Thanks,

Confirm the SSH problem if you leave the 6.0rc11 NPK in /files and reboot. SSH service reports "Invalid" state. If you start it manually (set ssh disabled=no), and then connect to TCP port 22, CPU jumps to 100% and stays there until reboot. 95% CPU reading is "unclassified" in the profiler. Have not tried the netinstall recovery.