Wallet was on Windows 7.
Only odd part of the debug log was
13 13:56:24 InstantSend : AllOutPointReady 0.000000, IsLockedInstantSendTransaction 0.000000, bool 1.000000
2018-03-13 13:56:24 InstantSend : AllOutPointReady 0.000000, IsLockedInstantSendTransaction 0.000000, bool 1.000000
repeated close to 100 times, one different statement in that run was
2018-03-13 13:56:24 InstantSend : AllOutPointReady 1.000000, IsLockedInstantSendTransaction 1.000000, bool 1.000000
2018-03-13 13:56:24 CInstantSend::ProcessTxLockRequest successful
2018-03-13 13:56:24 InstantSend : AllOutPointReady 1.000000, IsLockedInstantSendTransaction 1.000000, bool 1.000000
Then had
2018-03-13 13:56:29 InstantSend : AllOutPointReady 1.000000, IsLockedInstantSendTransaction 1.000000, bool 1.000000
2018-03-13 13:57:32 UpdateTip: new best=76c342e700a149155566862dc4ecda777398cf95442ed8bbd0b5ac41be8629b7 height=34370 log2_work=58.86532 tx=130988 date=2018-03-13 13:57:00 progress=0.999998 cache=1.8MiB(2269tx)
2018-03-13 13:57:32 ProcessNewBlock : ACCEPTED
2018-03-13 13:57:49 CInstantSend::CreateTxLockCandidate -- new, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24
2018-03-13 13:57:49 CInstantSend::ProcessTxLockRequest -- accepted, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24
2018-03-13 13:57:49 InstantSend : AllOutPointReady 0.000000, IsLockedInstantSendTransaction 0.000000, bool 1.000000
2018-03-13 13:57:49 CInstantSend::ProcessTxLockRequest successful
2018-03-13 13:57:49 TXLOCKREQUEST -- Transaction Lock Request accepted, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24, peer=816
2018-03-13 13:57:49 CInstantSend::CreateTxLockCandidate -- creating birth, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24
2018-03-13 13:57:49 CInstantSend::CreateTxLockCandidate -- update empty, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24
2018-03-13 13:57:49 CInstantSend::ProcessTxLockRequest -- accepted, txid=157a2f1520b375523a3ea5cabef282eeaed7993b412ce40b138c456ae481ff24
2018-03-13 13:57:49 InstantSend : AllOutPointReady 0.000000, IsLockedInstantSendTransaction 0.000000, bool 1.000000
Also for some reason after updating to 1.1.1.1 the whole thing crashed (overnight)
last lines before the crash were
2018-03-14 10:37:57 ProcessNewBlock : ACCEPTED
2018-03-14 10:43:39 VerifyDistributedBurnTransaction::PASS for CPID A895052039C2E80B20C388ACC8AC47E1
2018-03-14 10:43:43 VerifyDistributedBurnTransaction::PASS for CPID A895052039C2E80B20C388ACC8AC47E1
2018-03-14 16:29:41