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Case Study #197 — 300 Software Failure Case Studies

Zoom August 2020 global service outage

Zoom, then seeing record usage during the COVID-19 pandemic, went down for several hours worldwide, disrupting online classes, remote work meetings, and telehealth appointments for millions of users.

2020-08-24
When it happened
Technology
Sector
#197 of 300
Ranked by documented impact
01 — What Happened

The damage was public. The root cause was preventable.

Zoom, then seeing record usage during the COVID-19 pandemic, went down for several hours worldwide, disrupting online classes, remote work meetings, and telehealth appointments for millions of users.

Technology
Sector affected
2020-08-24
Date of the event
#197
Rank in the 300 Software Failure Case Studies
1
Distinct root-cause clause identified below
02 — The Root Cause

What the software actually got wrong

Zoom attributed the outage to a problem within its own infrastructure that degraded connectivity for a significant portion of users, rather than any external attack, at a time when its systems were already under unprecedented pandemic-driven load.

01Root Cause

Zoom attributed the outage to a problem within its...

What Happened

Zoom attributed the outage to a problem within its own infrastructure that degraded connectivity for a significant portion of users, rather than any external attack, at a time when its systems were already under unprecedented pandemic-driven load.

How Requs AI Catches This

Requs AI Edge Case flags this exact pattern at the requirements and architecture stage — before a single line of code implementing it exists — so the assumption behind it gets challenged while it is still cheap to fix.

03 — How This Gets Caught Before It Happens

Beyond code coverage and "shall" testing

Root causes like this one rarely show up in code coverage or requirements-compliance testing, because nobody wrote a requirement anticipating the specific edge case that broke. Requs AI Edge Case and Requs AI Software FMEA are built to surface exactly this class of overlooked failure mode — before the software is written.

Requs AI Edge Case

Surfaces this before code exists

Identifies edge cases like this one at requirements and architecture time, using the Common Defect Enumeration to catalog failure patterns seen across hundreds of real-world software failures — including this one.

Requs AI Software FMEA

Connects the failure mode to the hazard

Traces this class of root cause directly to the system-level hazard it can produce, so a defect pattern like this one gets flagged during design review instead of after it ships.

Find the overlooked root causes before they ship.

Schedule a demonstration, or explore how Requs AI Edge Case and Software FMEA use the Common Defect Enumeration.