Here is the snippet from my dmesg log. There is a big gap from 14s to 513s! I don't have a clue how to troubleshoot this delay.
[ 10.862848] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready [ 14.520535] e1000e: eth0 NIC Link is Up 1000 Mbps Full Duplex, Flow Control: None [ 14.520565] IPv6: ADDRCONF(NETDEV_CHANGE): eth0: link becomes ready [ 513.374380] FS-Cache: Loaded [ 513.413373] RPC: Registered named UNIX socket transport module. With network-related messages near the gap, I'd suppose your computer was waiting for DHCP configuration for eth0 interface to complete.
If your computer wasn't connected to any network (eth0 most probably implies RJ-45 Ethernet socket), the boot script was simply waiting for the request to time out. In case not being connected is typical for this computer, I'd suggest to remove eth0 from /etc/network/interfaces to avoid configuring it at boot time.
If your computer was connected (and expected to be configured via DHCP), I'd suspect an issue with the router configuration. Maybe the router was temporarily out of service (rebooting?), or the IP address pool was depleted, or your MAC address got blacklisted somehow.
