I just got back to my home PC, after restarting this morning I see the error occurred again.
Sync was 1 year and 17 weeks behind, error is "Error: A fatal internal error occurred, see debug.log for details."
debug.log is a rather huge file, the end is as follows:
2015-07-13 13:58:10 UpdateTip: new best=00000000000000000ef5c4a6f6a2559ba5452031ca0b21e6aee9ea75c3228c5c height=290078 log2_work=77.202684 tx=34638586 date=2014-03-11 19:17:58 progress=0.198562 cache=62.9MiB(27370tx)
2015-07-13 13:58:10 UpdateTip: new best=0000000000000000bb67842942050e16f8be923fa234f185fcb6aa7406790444 height=290079 log2_work=77.20282 tx=34639235 date=2014-03-11 19:29:51 progress=0.198566 cache=63.9MiB(28440tx)
2015-07-13 13:58:10 UpdateTip: new best=0000000000000000769d317df34a88e6cada3d48b44b099415740ab22576dbde height=290080 log2_work=77.202956 tx=34640372 date=2014-03-11 19:50:40 progress=0.198573 cache=65.4MiB(30093tx)
2015-07-13 13:58:10 Corruption: block checksum mismatch
2015-07-13 13:58:10 *** System error while flushing: Database corrupted
2015-07-13 14:14:57 UPnP Port Mapping successful.
2015-07-13 14:17:05 socket sending timeout: 1201s
2015-07-13 14:17:42 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:18:09 socket sending timeout: 1201s
2015-07-13 14:34:57 UPnP Port Mapping successful.
2015-07-13 14:54:57 UPnP Port Mapping successful.
2015-07-13 15:14:57 UPnP Port Mapping successful.
2015-07-13 15:34:58 UPnP Port Mapping successful.
2015-07-13 15:54:58 UPnP Port Mapping successful.
2015-07-13 16:14:58 UPnP Port Mapping successful.
2015-07-13 16:34:58 UPnP Port Mapping successful.
2015-07-13 16:54:58 UPnP Port Mapping successful.
2015-07-13 17:14:58 UPnP Port Mapping successful.
2015-07-13 17:34:58 UPnP Port Mapping successful.
2015-07-13 17:54:58 UPnP Port Mapping successful.
2015-07-13 18:14:59 UPnP Port Mapping successful.
2015-07-13 18:34:59 UPnP Port Mapping successful.
2015-07-13 18:54:59 UPnP Port Mapping successful.
2015-07-13 19:14:59 UPnP Port Mapping successful.
2015-07-13 19:34:59 UPnP Port Mapping successful.