Suggest looking in /var/log/syslog and/or running "Boot Chart", plus the usual troubleshooting steps of removing peripherals and adding them one by one to eliminate possibilities or narrow things down. There are also the Ask Ubuntu and Ubuntu MATE forums which while not support forums per se can assist in troubleshooting.
Suggest looking in /var/log/syslog and/or running "Boot Chart", plus the usual troubleshooting steps of removing peripherals and adding them one by one to eliminate possibilities or narrow things down. There are also the Ask Ubuntu and Ubuntu MATE forums which while not support forums per se can assist in troubleshooting.