When the microdrive died I shut down the computer and restarted, but I have a tool that saves the dmesg buffer when it's full, so I can still pull the last few error messages before the microdrive went haywire.
This is what the kernel said.
blk_update_request: I/O error, dev sdc, sector 2761152
sd 8:0:0:0: [sdc] tag#0 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE
sd 8:0:0:0: [sdc] tag#0 Sense Key : Unit Attention [current]
sd 8:0:0:0: [sdc] tag#0 Add. Sense: Not ready to ready change, medium may have changed
sd 8:0:0:0: [sdc] tag#0 CDB: Write(10) 2a 00 00 29 b5 a0 00 00 f0 00
Buffer I/O error on dev sdc, logical block 341684, lost async page write
Buffer I/O error on dev sdc, logical block 341685, lost async page write
Buffer I/O error on dev sdc, logical block 341686, lost async page write
Buffer I/O error on dev sdc, logical block 341687, lost async page write
Buffer I/O error on dev sdc, logical block 341688, lost async page write
Buffer I/O error on dev sdc, logical block 341689, lost async page write
Buffer I/O error on dev sdc, logical block 341690, lost async page write
Buffer I/O error on dev sdc, logical block 341691, lost async page write
Buffer I/O error on dev sdc, logical block 341692, lost async page write
Buffer I/O error on dev sdc, logical block 341693, lost async page write