Millions of users on O2 in UK are unable to use mobile data due to a software problem in Ericsson's equipment; SoftBank in Japan was affected for several hours
Millions of mobile phone users around the world have been unable to use their smartphones after a software issue in systems provided by Ericsson caused major disruption.
Context & Ripple Effects
This is a single-vendor failure with multi-continent reach: one software problem in [[a:|Ericsson]] equipment took down mobile data for millions of O2 subscribers in the UK and knocked SoftBank's Japanese network offline for several hours, showing how concentrated the radio-access supply chain is.
The corpus keeps returning to this failure mode. Optus later attributed a 10M+-customer blackout to changes made during a routine software upgrade, Verizon has twice suffered nationwide voice-and-data disruptions (September 2024 and again in January 2026), and O2 itself was back in the news when a network security flaw exposed user locations for up to two years. Against that backdrop, Opensignal still ranked Japan #1 in G7 mobile reliability — national averages can mask how fragile any single carrier day can be.
First-order effects
- Millions of O2 UK customers lose mobile data outright, and SoftBank's Japanese subscribers lose service for several hours, with both carriers bearing the customer-service load and reputational damage for a fault rooted in their shared supplier.
- Ericsson faces immediate escalation from two flagship customers on two continents, putting its software release and quality-assurance processes under direct commercial scrutiny.
Second-order effects
- Carriers running the same Ericsson gear elsewhere must decide whether to halt or roll back affected software versions, while rival operators market against the downtime window to capture displaced traffic.
- Procurement teams at O2, SoftBank, and their peers gain leverage to demand staged rollouts, rollback guarantees, and penalty clauses from Ericsson — pricing resilience into future radio-access contracts.
Third-order effects
- If the pattern holds — Optus's upgrade-triggered outage, Verizon's repeated blackouts, this Ericsson fault — regulators move from treating outages as customer-service incidents to auditing change-management and vendor-concentration risk in national telecoms.
- Operators structurally diversify or dual-source network software so no single vendor update can silence data service across an entire country at once.
The trend: Carrier outages increasingly trace to single-vendor software faults rather than local hardware failures, turning supplier concentration and update discipline into core network-resilience questions for operators and regulators alike.