Tack för tipset! En del av dmesg gav en del röda partier, nedan är den sista delen innan promten. Det kanske kan ge några ledtrådar
Disken med LMDE är inte bortkopplad men den syns inte någonstans, inte ens med en live dist igång.
724.485837] ata3: exception Emask 0x50 SAct 0x0 SErr 0x800 action 0x6 frozen
[ 724.485844] ata3: irq_stat 0x08000000, interface fatal error
[ 724.485851] ata3: SError: { HostInt }
[ 724.485860] ata3: hard resetting link
[ 734.485964] ata3: softreset failed (1st FIS failed)
[ 734.485973] ata3: hard resetting link
[ 744.490237] ata3: softreset failed (1st FIS failed)
[ 744.490252] ata3: hard resetting link
[ 779.491127] ata3: softreset failed (1st FIS failed)
[ 779.491145] ata3: hard resetting link
[ 784.683315] ata3: SATA link up 1.5 Gbps (SStatus 113 SControl 310)
[ 784.683328] ata3.00: link online but device misclassified
[ 784.683335] ata3: link online but 1 devices misclassified, device detection might fail
[ 784.683365] ata3: EH complete
[ 784.683388] ata3: exception Emask 0x50 SAct 0x0 SErr 0x800 action 0x6 frozen
[ 784.683395] ata3: irq_stat 0x08000000, interface fatal error
[ 784.683402] ata3: SError: { HostInt }
[ 784.683411] ata3: hard resetting link
[ 794.687512] ata3: softreset failed (1st FIS failed)
[ 794.687527] ata3: hard resetting link
[ 804.687755] ata3: softreset failed (1st FIS failed)
[ 804.687770] ata3: hard resetting link