Apple's iCloud had trouble overnight.
Between about 11 p.m. PT Wednesday and 6:30 a.m. PT on Thursday, Apple's iCloud services, including account sign-in, Find My iPhone, and Mail, were responding slowly for "some users," Apple's System Status Dashboard showed. The dashboard didn't initially specify how many people were affected. But after the issue was fixed, it noted that about 40 percent of users were affected. The last time Apple announced iCloud user figures was in 2013 when it had 320 million users, so it's likely that the problem affected hundreds of millions of people.
Apple's iCloud is part synching platform, part storage solution. Customers who own the company's OS X- or iOS-based products have access to iCloud, allowing them to sync information across different devices, use Apple's iWork productivity suite, and access e-mail.
iCloud is a critical component for many people. Its backup feature, for instance, can automatically backup an Apple product to the cloud, ensuring that if a device fails or if customers buy a new product, they can quickly get all of their information on the new Apple device.
iCloud has fallen victim to some issues over the years. In 2012, for instance, the platform was affected by a two-day outage. A year later, iCloud had an early-morning outage, followed by another a year later. Those issues affected millions, Apple said at the time.
Keeping online services up and running all the time is nearly impossible for any company. Several tech giants, including Apple, Google, Sony, Microsoft and Yahoo, are affected by issues at one time or another. In the vast majority of cases, the problems don't become lingering issues.
It's unclear what caused the iCloud problem, but so far, Apple's other platforms are unaffected. Apple's System Status Dashboard also includes information about its other services, such as iTunes. All of Apple's services are currently operational and show no problems.
Apple did not respond to a request for comment.
Update, 7:27 a.m. PT: iCloud services have been restored.