No reboot but booting after cutting AC power works fine?

smartctl -x sda

smartctl 6.5 2016-05-07 r4318 [x86_64-w64-mingw32-win8.1] (sf-6.5-1)
Copyright (C) 2002-16, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Family: Toshiba 3.5" DT01ACA... Desktop HDD
Device Model: TOSHIBA DT01ACA100
Serial Number: 24H2L2LFS
LU WWN Device Id: 5 000039 ff7eb7323
Firmware Version: MS2OA750
User Capacity: 1 000 204 886 016 bytes [1,00 TB]
Sector Sizes: 512 bytes logical, 4096 bytes physical
Rotation Rate: 7200 rpm
Form Factor: 3.5 inches
Device is: In smartctl database [for details use: -P show]
ATA Version is: ATA8-ACS T13/1699-D revision 4
SATA Version is: SATA 3.0, 6.0 Gb/s (current: 6.0 Gb/s)
Local Time is: Wed Dec 14 14:45:51 2016
SMART support is: Available - device has SMART capability.
SMART support is: Enabled
AAM feature is: Unavailable
APM level is: 128 (minimum power consumption without standby)
Rd look-ahead is: Enabled
Write cache is: Enabled
ATA Security is: Disabled, frozen [SEC2]
Wt Cache Reorder: Enabled

=== START OF READ SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

General SMART Values:
Offline data collection status: (0x84) Offline data collection activity
was suspended by an interrupting command
from host.
Auto Offline Data Collection: Enabled.
Self-test execution status: ( 0) The previous self-test routine completed

without error or no self-test has ever
been run.
Total time to complete Offline
data collection: ( 7458) seconds.
Offline data collection
capabilities: (0x5b) SMART execute Offline immediate.
Auto Offline data collection on/off supp
ort.
Suspend Offline collection upon new
command.
Offline surface scan supported.
Self-test supported.
No Conveyance Self-test supported.
Selective Self-test supported.
SMART capabilities: (0x0003) Saves SMART data before entering
power-saving mode.
Supports SMART auto save timer.
Error logging capability: (0x01) Error logging supported.
General Purpose Logging supported.
Short self-test routine
recommended polling time: ( 1) minutes.
Extended self-test routine
recommended polling time: ( 125) minutes.
SCT capabilities: (0x003d) SCT Status supported.
SCT Error Recovery Control supported.
SCT Feature Control supported.
SCT Data Table supported.

SMART Attributes Data Structure revision number: 16
Vendor Specific SMART Attributes with Thresholds:
ID# ATTRIBUTE_NAME FLAGS VALUE WORST THRESH FAIL RAW_VALUE
1 Raw_Read_Error_Rate PO-R-- 099 099 016 - 65537
2 Throughput_Performance P-S--- 141 141 054 - 74
3 Spin_Up_Time POS--- 125 125 024 - 185 (Average 183)
4 Start_Stop_Count -O--C- 100 100 000 - 562
5 Reallocated_Sector_Ct PO--CK 100 100 005 - 0
7 Seek_Error_Rate PO-R-- 100 100 067 - 0
8 Seek_Time_Performance P-S--- 118 118 020 - 33
9 Power_On_Hours -O--C- 100 100 000 - 3070
10 Spin_Retry_Count PO--C- 100 100 060 - 0
12 Power_Cycle_Count -O--CK 100 100 000 - 512
192 Power-Off_Retract_Count -O--CK 100 100 000 - 563
193 Load_Cycle_Count -O--C- 100 100 000 - 563
194 Temperature_Celsius -O---- 206 206 000 - 29 (Min/Max 19/41)
196 Reallocated_Event_Count -O--CK 100 100 000 - 0
197 Current_Pending_Sector -O---K 100 100 000 - 0
198 Offline_Uncorrectable ---R-- 100 100 000 - 0
199 UDMA_CRC_Error_Count -O-R-- 200 200 000 - 0
||||||_ K auto-keep
|||||__ C event count
||||___ R error rate
|||____ S speed/performance
||_____ O updated online
|______ P prefailure warning

General Purpose Log Directory Version 1
SMART Log Directory Version 1 [multi-sector log support]
Address Access R/W Size Description
0x00 GPL,SL R/O 1 Log Directory
0x01 SL R/O 1 Summary SMART error log
0x03 GPL R/O 1 Ext. Comprehensive SMART error log
0x04 GPL R/O 7 Device Statistics log
0x06 SL R/O 1 SMART self-test log
0x07 GPL R/O 1 Extended self-test log
0x08 GPL R/O 2 Power Conditions log
0x09 SL R/W 1 Selective self-test log
0x10 GPL R/O 1 SATA NCQ Queued Error log
0x11 GPL R/O 1 SATA Phy Event Counters log
0x20 GPL R/O 1 Streaming performance log [OBS-8]
0x21 GPL R/O 1 Write stream error log
0x22 GPL R/O 1 Read stream error log
0x80-0x9f GPL,SL R/W 16 Host vendor specific log
0xe0 GPL,SL R/W 1 SCT Command/Status
0xe1 GPL,SL R/W 1 SCT Data Transfer

SMART Extended Comprehensive Error Log Version: 1 (1 sectors)
No Errors Logged

SMART Extended Self-test Log Version: 1 (1 sectors)
No self-tests have been logged. [To run self-tests, use: smartctl -t]

SMART Selective self-test log data structure revision number 1
SPAN MIN_LBA MAX_LBA CURRENT_TEST_STATUS
1 0 0 Not_testing
2 0 0 Not_testing
3 0 0 Not_testing
4 0 0 Not_testing
5 0 0 Not_testing
Selective self-test flags (0x0):
After scanning selected spans, do NOT read-scan remainder of disk.
If Selective self-test is pending on power-up, resume after 0 minute delay.

SCT Status Version: 3
SCT Version (vendor specific): 256 (0x0100)
SCT Support Level: 1
Device State: SMART Off-line Data Collection executing in
background (4)
Current Temperature: 29 Celsius
Power Cycle Min/Max Temperature: 21/30 Celsius
Lifetime Min/Max Temperature: 19/41 Celsius
Under/Over Temperature Limit Count: 0/0

SCT Temperature History Version: 2
Temperature Sampling Period: 1 minute
Temperature Logging Interval: 1 minute
Min/Max recommended Temperature: 0/60 Celsius
Min/Max Temperature Limit: -40/70 Celsius
Temperature History Size (Index): 128 (91)

Index Estimated Time Temperature Celsius
92 2016-12-14 12:38 29 **********
... ..( 2 skipped). .. **********
95 2016-12-14 12:41 29 **********
96 2016-12-14 12:42 30 ***********
... ..( 5 skipped). .. ***********
102 2016-12-14 12:48 30 ***********
103 2016-12-14 12:49 29 **********
... ..( 12 skipped). .. **********
116 2016-12-14 13:02 29 **********
117 2016-12-14 13:03 30 ***********
118 2016-12-14 13:04 29 **********
... ..(100 skipped). .. **********
91 2016-12-14 14:45 29 **********

SCT Error Recovery Control:
Read: Disabled
Write: Disabled

Device Statistics (GP Log 0x04)
Page Offset Size Value Flags Description
0x01 ===== = = === == General Statistics (rev 1) ==
0x01 0x008 4 512 --- Lifetime Power-On Resets
0x01 0x010 4 3070 --- Power-on Hours
0x01 0x018 6 19419889447 --- Logical Sectors Written
0x01 0x020 6 229297423 --- Number of Write Commands
0x01 0x028 6 23189001911 --- Logical Sectors Read
0x01 0x030 6 312265619 --- Number of Read Commands
0x03 ===== = = === == Rotating Media Statistics (rev 1) ==
0x03 0x008 4 3068 --- Spindle Motor Power-on Hours
0x03 0x010 4 3068 --- Head Flying Hours
0x03 0x018 4 563 --- Head Load Events
0x03 0x020 4 0 --- Number of Reallocated Logical Sectors
0x03 0x028 4 116 --- Read Recovery Attempts
0x03 0x030 4 2 --- Number of Mechanical Start Failures
0x04 ===== = = === == General Errors Statistics (rev 1) ==
0x04 0x008 4 0 --- Number of Reported Uncorrectable Errors
0x04 0x010 4 0 --- Resets Between Cmd Acceptance and Completio
n
0x05 ===== = = === == Temperature Statistics (rev 1) ==
0x05 0x008 1 29 --- Current Temperature
0x05 0x010 1 29 N-- Average Short Term Temperature
0x05 0x018 1 31 N-- Average Long Term Temperature
0x05 0x020 1 41 --- Highest Temperature
0x05 0x028 1 19 --- Lowest Temperature
0x05 0x030 1 37 N-- Highest Average Short Term Temperature
0x05 0x038 1 25 N-- Lowest Average Short Term Temperature
0x05 0x040 1 35 N-- Highest Average Long Term Temperature
0x05 0x048 1 25 N-- Lowest Average Long Term Temperature
0x05 0x050 4 0 --- Time in Over-Temperature
0x05 0x058 1 60 --- Specified Maximum Operating Temperature
0x05 0x060 4 0 --- Time in Under-Temperature
0x05 0x068 1 0 --- Specified Minimum Operating Temperature
0x06 ===== = = === == Transport Statistics (rev 1) ==
0x06 0x008 4 690 --- Number of Hardware Resets
0x06 0x010 4 123 --- Number of ASR Events
0x06 0x018 4 0 --- Number of Interface CRC Errors
|||_ C monitored condition met
||__ D supports DSN
|___ N normalized value

SATA Phy Event Counters (GP Log 0x11)
ID Size Value Description
0x0001 2 0 Command failed due to ICRC error
0x0002 2 0 R_ERR response for data FIS
0x0003 2 0 R_ERR response for device-to-host data FIS
0x0004 2 0 R_ERR response for host-to-device data FIS
0x0005 2 0 R_ERR response for non-data FIS
0x0006 2 0 R_ERR response for device-to-host non-data FIS
0x0007 2 0 R_ERR response for host-to-device non-data FIS
0x0009 2 1 Transition from drive PhyRdy to drive PhyNRdy
0x000a 2 0 Device-to-host register FISes sent due to a COMRESET
0x000b 2 0 CRC errors within host-to-device FIS
0x000d 2 0 Non-CRC errors within host-to-device FIS


Type <return> to exit:

Sorry for just blurting out the results from smartmontools. No intent to be impolite

Thanks!

I agree. Used to work in the industry but it's been ages since I fiddled with PCs. Thanks for the tip on checking the SMART data

I'll be off buying a new disk, then. Any ideas on how to best backup and replace? RAID/mirror and then take the old disk offline?

Oh, forgot. Why the consequent boot success when starting from power off if the disk is the sole culprit? Thinking of the possibility of there being other problems (motherboard or so) too.