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Y2K Timeline

In brief: The two-digit year problem was spotted decades before it became urgent. It was flagged in print in 1971, mostly ignored through the 1980s, and pushed into the mainstream in 1993. Between 1997 and 1999 it triggered laws, presidential orders and international coordination. This page lists the key events in date order, from the first warnings through rollover night to the leap day of 29 February 2000 and the wind-down that followed.

Risk level n/a (historical)
Status Complete. Post-2000 echoes are listed in Related-Date-Bugs
Last reviewed 2026-10-21

Overview

Y2K took about 30 years to go from a known defect to a funded global programme. The early warnings were ignored because the deadline seemed far away and fixing it was expensive, which is the same situation the Year 2038 problem is in today. Most of the work was done in roughly 1995–1999 [1]. The institutions that ran it, including the President's Council, the Senate Special Committee, Action 2000 and the International Y2K Cooperation Center, were all set up in the last two to three years before the deadline.

The table below uses the most specific date available. Where only a month or year is known, only that is shown.

Chronology

Early warnings (1958–1993)

Date Event Ref
1958 Bob Bemer is reported to have noticed the two-digit-year issue while working on genealogical software (secondary source only) [2]
1960s IBM's System/360, the industry-standard machine of the decade, ships with two-digit dates, which entrenches the format [3]
1971 Bemer publishes "What's the Date?" in the Honeywell Computer Journal, the first public identification of the problem [4]
1970s The International Standards Organization adopts a four-digit year standard but cannot reverse established practice [3]
c. 1974 The Pentagon promises to adopt century-friendly dates but does not act [3]
1979 Bemer warns again in "Time and the Computer", Interface Age [4]
1982 Bemer retires, his warnings largely dismissed [3]
1993-09-06 Peter de Jager's "Doomsday 2000" appears in Computerworld [5][6]
1993-09-16 De Jager estimates Y2K costs at $75 billion in Computerworld [7]

Mobilisation (1997–1998)

Date Event Ref
1997 (by fall) Only 9% of Canadian businesses have a formal Y2K plan [6]
1997-10 UK trade secretary Margaret Beckett announces Action 2000 as the government-backed successor to Taskforce 2000 [8]
1998-02-04 President Clinton signs Executive Order 13073, creating the President's Council on Year 2000 Conversion, chaired by an Assistant to the President (John Koskinen) [9][10]
1998-02-10 GAO testifies on the FDIC's oversight of bank Y2K readiness (T-AIMD-98-73). Its recommendations covered examination procedures, testing and contingency-planning guidance, and were later marked implemented [25]
1998-04 The U.S. Senate Special Committee on the Year 2000 Technology Problem is established (Chairman Robert F. Bennett, Vice-Chairman Christopher J. Dodd) [1]
1998-10-19 Year 2000 Information and Readiness Disclosure Act (Pub. L. 105-271) becomes law. It limits liability for good-faith Y2K disclosures [1]
1998-12 First global meeting of national Y2K coordinators at the UN (over 120 countries) [11]
1998-12-13 Action 2000's Gwynneth Flower advises UK households to stock two weeks of long-life food for the following Christmas [12]

Final year (1999)

Date Event Ref
1999-02 International Y2K Cooperation Center (IY2KCC) is founded under the UN Working Group on Informatics with World Bank funding. Bruce W. McConnell is director [11]
1999-02-24 Senate committee's "100 day report" (S. Prt. 106-10) [1]
1999-06-22 Second global meeting of national Y2K coordinators at UN Headquarters [13]
1999-07-20 Y2K Act (Pub. L. 106-31) becomes law, to discourage frivolous Y2K lawsuits [1]
1999-08-21/22 First GPS week-number rollover, a related date bug (see GPS-Week-Rollover) [14]
1999-09-22 Senate committee's report S. Prt. 106-31 [1]
1999-11 U.S. Commerce Department estimates repairs at "at least $100 billion", possibly $114 billion [7]
1999-12 A USA Today/NSF poll finds 7% of adults expect major problems [7]
1999-12-29 Charlotte, NC 911 systems break down during Y2K testing [1]
1999-12-30 The White House Information Coordination Center (ICC) begins round-the-clock monitoring, which runs until 3 Jan 2000 [15]
1999-12-31 A Y2K patch causes a failure at a U.S. intelligence-satellite ground station. Processing is blinded for hours and degraded for more than two days [16]

Rollover and after (2000)

Date Event Ref
2000-01-01 Rollover. Minor failures: U.S. Naval Observatory website shows "19100" [17]
2000-01-01 Japanese nuclear plants (Onagawa, Shika, Fukushima No. 2) report minor monitoring and display faults with no safety impact [18]
2000-01-01 Delaware racetrack slot machines fail briefly. Reports give about 150 machines at three tracks [19], or 800 [1] [1][19]
2000-01-27 GAO testifies that rollover disruptions were limited (T-AIMD-00-70) [20]
2000-02-16 IY2KCC releases its closing report, Y2K: Starting the Century Right! [11]
2000-02-29 Leap day. Scattered failures, including Japanese weather stations, Japan Post ATMs and a Boston hotel key system [21]
2000-02-29 The Senate Special Committee issues its final report, Y2K Aftermath – Crisis Averted, and disbands [1]
2000-03-01 IY2KCC scheduled to disband [11]
2000-03-29 President's Council final report, The Journey to Y2K, is published (date from a secondary source) [22]
2000-03-31 President's Council on Year 2000 Conversion ends [15][22]
2000-05 Sheffield (UK) Down's syndrome screening error caused by a Y2K age bug is discovered and fixed (reported as 24 May), months after rollover [2][23]
2000-09-12 GAO publishes Lessons Learned Can Be Applied to Other Management Challenges (AIMD-00-290) [24]

Technical details

Three things happened in sequence on the night itself:

  1. Pre-rollover look-ahead failures. Systems that calculate future dates (expiry, scheduling, forecasting) hit Y2K in 1999 or earlier. Testing also caused failures, as in Charlotte's 911 system on 29 December [1]. The spy-satellite ground-station failure was caused by the Y2K patch itself, which had been tested in parts but never as a whole system [16].
  2. Midnight UTC and local midnights. Failures came in waves by time zone. Japan was one of the first industrial countries to roll over, which made its reports an early warning [18].
  3. Post-rollover business cycles. Problems in month-end, quarter-end and leap-day processing appeared weeks later. The Senate committee expected "continued reports of minor nuisances throughout 2000" [1].

See also

References

  1. Y2K Aftermath – Crisis Averted: Final Committee Report (S. Prt. 106-42) — U.S. Senate Special Committee on the Year 2000 Technology Problem, 29 Feb 2000. Committee dates, both Acts, earlier reports, and incidents.
  2. Year 2000 problem — Wikipedia. Bemer's 1958 observation (secondary).
  3. The History and the Hype — Chris Taylor, Time, 18 Jan 1999. System/360, ISO, the Pentagon, and Bemer's retirement.
  4. Guide to the Robert W. Bemer Papers — Computer History Museum (OAC). Bemer's 1971 and 1979 articles.
  5. Have we learned nothing from Y2K? — Computerworld, 1 Jan 2000. De Jager's article, 6 Sep 1993.
  6. Y2K: The strange, true history of how Canada prepared… — The Globe and Mail, 28 Dec 2019. The "Doomsday 2000" spread and the 9% figure.
  7. Some Key Facts and Events in Y2K History — Computerworld, 3 Jan 2000. The $75bn (1993) and $100–114bn (1999) estimates and the December 1999 poll.
  8. 1997 REVIEW: The year of blitz and PCs — Computing. Beckett announces Action 2000, October 1997.
  9. Executive Order 13073—Year 2000 Conversion — The American Presidency Project, 4 Feb 1998. Creates the President's Council.
  10. Press briefing by John Koskinen on Y2K conversion — Clinton White House archive, 14 Jul 1998. Koskinen as Council chair.
  11. IY2KCC Issues Closing Report on Global Y2K Effort — U.S. Department of State (usinfo), 16 Feb 2000. IY2KCC founding, funding, director and closure.
  12. UK Y2K supremo says plan for Armageddon — John Lettice, The Register, 13 Dec 1998. Flower's stockpiling advice.
  13. Press conference on global meeting of Y2K coordinators — United Nations, 22 Jun 1999. The second global meeting.
  14. GPS Week Number Rollover — GPS.gov (archive). First rollover in August 1999.
  15. President's Y2K council disbands — Diane Frank, FCW (Nextgov), 3 Apr 2000. ICC hours and the Council staying open through leap day.
  16. Pentagon Y2K satellite problem — Voice of America (via FAS), 13 Jan 2000. Ground-station failure caused by the patch.
  17. Y2K glitch a 'black eye' for Naval Observatory — Computerworld, 1 Jan 2000. The "19100" display.
  18. Japan Y2K rollover marred by N-plant glitches — Deseret News, 3 Jan 2000. Japanese nuclear plant faults.
  19. Some Y2K glitches reported around U.S. — Deseret News, 2 Jan 2000. About 150 Delaware slot machines.
  20. Year 2000 Computing Challenge: Leadership and Partnerships Result in Limited Rollover Disruptions (T-AIMD-00-70) — GAO, 27 Jan 2000.
  21. Leap day skips past with few problems — Computerworld, 1 Mar 2000.
  22. The Journey to Y2K: Final Report of the President's Council on Year 2000 Conversion — The IT Law Wiki. Report date 29 Mar 2000 and Council end 31 Mar 2000 (secondary; full report text not retrieved).
  23. Y2K Bug Blamed For Miscalculated Down Syndrome Risk — Slashdot, 13 Sep 2001 (relaying BBC News).
  24. Year 2000 Computing Challenge: Lessons Learned Can Be Applied to Other Management Challenges (AIMD-00-290) — GAO, 12 Sep 2000.
  25. Year 2000 Computing Crisis: Federal Deposit Insurance Corporation's Efforts to Ensure Bank Systems Are Year 2000 Compliant (T-AIMD-98-73) — GAO, 10 Feb 1998. Banking oversight testimony; FFIEC vendor, testing and contingency guidance followed in March–May 1998.