oh ... k. Nope, DB wasn't in use by any Moz / other process last run caught some additional log: sqlite> pragma integrity_check; *** in database main *** Page 6835: unable to get the page. error code=266 Page 6834: unable to get the page. error code=266 Page 6833: unable to get the page. error code=266 Memory Used: 2282200 (max 2292088) bytes Number of Outstanding Allocations: 1119 (max 1137) Number of Pcache Overflow Bytes: 1995760 (max 2004112) bytes Largest Allocation: 85120 bytes Largest Pcache Allocation: 4256 bytes Lookaside Slots Used: 123 (max 123) Successful lookaside attempts: 572 Lookaside failures due to size: 5 Lookaside failures due to OOM: 1139 Pager Heap Usage: 2080408 bytes Page cache hits: 198230 Page cache misses: 30157 Page cache writes: 0 Page cache spills: 0 Schema Heap Usage: 12024 bytes Statement Heap/Lookaside Usage: 77840 bytes Fullscan Steps: 0 Sort Operations: 0 Autoindex Inserts: 0 Virtual Machine Steps: 861970 Reprepare operations: 0 Number of times run: 1 Memory used by prepared stmt: 77840 Error: disk I/O error then I tried a batch of integrity_check: Error: near line 1: disk I/O error Error: near line 2: disk I/O error ok Error: near line 4: disk I/O error Error: near line 5: disk I/O error *** in database main *** Page 7225: unable to get the page. error code=266 Page 7176: unable to get the page. error code=266 Page 7115: unable to get the page. error code=266 Page 4993: unable to get the page. error code=266 Page 4992: unable to get the page. error code=266 Page 4937: unable to get the page. error code=266 Error: near line 6: disk I/O error Error: near line 7: disk I/O error Error: near line 8: disk I/O error Error: near line 9: disk I/O error Error: near line 10: disk I/O error ok Error: near line 12: disk I/O error Error: near line 13: disk I/O error while monitoring the cpu/mem usage of MS' antimalware which seemed to spike, so the AV interference might be a thing. At this point I fired windows-update & reboot ... now all seem fine: sqlite> .read ic.sql ok ok ok ok ok ok ok ok ok ok ok ok ok each 'ok' is from a integrity_check line in the script. So whether the culprit was some system bug, AV bug or just memory crap piled up is not clear, but the AV interference sound a sensible option. Wonder if the lib/tool can be made more robust on that. Anyway, so far my issue seems gone, thanx all!