Microsoft has blamed a network upgrade fault for a global outage that left police unable to receive online crime reports and NHS staff using paper records, as disruption spread across public services, schools and businesses.

The company said on Friday afternoon that it was “deeply sorry” and seeing “broad recovery” after services began failing from 6pm GMT on Thursday. It said the incident was not related to a cyberattack or artificial intelligence agents.

According to Microsoft, a fault introduced during an earlier network capacity upgrade surfaced following a recent network change. The underlying issue had been addressed, but services were being restored gradually across remaining customers and regions. The company said checking stability at each stage took longer but helped ensure a stable restoration.

Millions of customers were unable to send or receive Outlook emails. Teams, Copilot and other Microsoft 365 services were also disrupted. Downdetector recorded a rise in UK Teams problem reports at about 6.15pm on Thursday; US Outlook reports exceeded 130,000 at their peak that night. Users later reported email services returning.

The consequences showed how failures in workplace systems can reach people seeking public services. Police forces directed people to telephone 101 or 999 rather than submit crime reports online. NHS England said staff were using established contingency measures, including paper records, and urged patients to attend appointments and continue using 999 and 111 when necessary.

The National Pharmacy Association warned that disruption to NHS email could delay some prescriptions. Councils reported affected services, while National Rail warned that passengers might struggle to retrieve tickets from their emails.

Cyber minister Baroness Lloyd of Effra said the disruption mainly affected back-office functions, though there were “limited reports of impact on frontline service delivery”. She described the incident as “inconvenient and disruptive” and said she had spoken to Microsoft UK chief executive Darren Hardman. The UK Government and governments elsewhere introduced contingency measures.

Tina McKenzie, national chairman of the Federation of Small Businesses, said small firms would be left “floundering by this mass outage”. She also warned that criminals might exploit the disruption through fake offers of assistance.

OpenAI’s ChatGPT and Anthropic’s Claude also experienced disruption; no connection to Microsoft’s technical fault was established in the account of those problems.

Microsoft has promised a full post-incident report once its review is complete. Its explanation identifies the sequence behind the failure, but the detailed findings remain outstanding.