This is some sort of disk corruption. Did you lose electricity while syncing, and do you see any "Press any key in 10 seconds to abort disk check" when you start the computer?

Both of these can destroy the blockchain copy. In any case, try opening File Explorer, type to %Userprofile%/AppData/Roaming/Bitcoin in the address bar, delete the entire folder (copy the wallets folder if you created a wallet.dat though) and then start Bitcoin Core again - this will reset all the state to zero but it will start syncing again.

Day: 4

Day 11:

Day 1




{
  "chain": "main",
  "blocks": 98367,
  "headers": 896594,
  "bestblockhash": "00000000000106f30bc423e08e5b0e4b5a8480932c8d3047b76587c0641e0a53",
  "bits": "1b055953",
  "target": "0000000000055953000000000000000000000000000000000000000000000000",
  "difficulty": 12251.9997603745,
  "time": 1292759164,
  "mediantime": 1292757306,
  "verificationprogress": 0.000176741565038317,
  "initialblockdownload": true,
  "chainwork": "00000000000000000000000000000000000000000000000004ea0c4b148dcb20",
  "size_on_disk": 68359339,
  "pruned": true,
  "pruneheight": 0,
  "automatic_pruning": true,
  "prune_target_size": 1999634432,
  "warnings": [
  ]
}

Day 8:

Day 8

I just did the correction, you can check it out now and see if everything is okay. I edited the previous post and I pasted the corrected one. Thanks for pointing it out.

I wish to start the challenge afresh after stopping at day three (3) because of some technical difficulties.
Day 1

{
  "chain": "main",
  "blocks": 214552,
  "headers": 865145,
  "bestblockhash": "00000000000002edac0357fb661761b0e546423d85633d365158642ac8eb7eaa",
  "difficulty": 3315466.687652757,
  "time": 1356531787,
  "mediantime": 1356513475,
  "verificationprogress": 0.007043563223616565,
  "initialblockdownload": true,
  "chainwork": "00000000000000000000000000000000000000000000001fd64e31ea7b64acd2",
  "size_on_disk": 736764556,
  "pruned": true,
  "pruneheight": 232654,
  "automatic_pruning": true,
  "prune_target_size": 1999634432,
  "warnings": ""
}

Day 1

{
  "chain": "main",
  "blocks": 247564,
  "headers": 896764,
  "bestblockhash": "00000000000000502b38996b6239ee1d9bd1750005a61bb980d6e0b3c91c18cb",
  "bits": "1a00a429",
  "target": "00000000000000a4290000000000000000000000000000000000000000000000",
  "difficulty": 26162875.6825699,
  "time": 1374329002,
  "mediantime": 1374327484,
  "verificationprogress": 0.01755394705201021,
  "initialblockdownload": true,
  "chainwork": "00000000000000000000000000000000000000000000006fcd9837000e7a6748",
  "size_on_disk": 1867159996,
  "pruned": true,
  "pruneheight": 235303,
  "automatic_pruning": true,
  "prune_target_size": 1999634432,
  "warnings": [
  ]
}

Day 2


{
  "chain": "main",
  "blocks": 485646,
  "headers": 875665,
  "bestblockhash": "00000000000000000066bdffc94361653cc464731c91be5cbf3f65ed33fac421",
  "difficulty": 1375533180235.136,
  "time": 1502657645,
  "mediantime": 1502692564,
  "verificationprogress": 0.2254137661856344,
  "initialblockdownload": true,
  "chainwork": "000000000000000000000000000000000000000000b0d646910b96b4b7618a3c",
  "size_on_disk": 1623745565,
  "pruned": true,
  "pruneheight": 485681,
  "automatic_pruning": true,
  "prune_target_size": 3698467664,
  "warnings": [
  ]
}