Some of the issues appear to have been resolved, but Apple's Game Center showed problems with user sign-ins reoccurring at 10:30 a.m. Pacific time, after issues earlier in the morning had been resolved.
Although Apple improved its Services, Stores and iCloud status page late last year, the company still does not publish much detail about the cause of service outages or the number of affected customers.
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"Users might have incorrectly received an authentication error when attempting to use iCloud," Apple says on its status page. "Setting up a new iCloud account from an eligible device may have been temporarily unavailable."
The company says that between 4:20 a.m. and 8:25 a.m. Pacific time, "Some users [were] affected." It also acknowledges that iTunes Store, Apple ID and Game Center were affected.
Although "some users" is not specific enough to be useful, at least Apple is providing a trickle of public information. Microsoft, another major provider of cloud services, does not make Office 365 data public, except to paying customers.
Asked to provide more detail, Apple did not respond. Apple public relations personnel seldom respond to press queries, but the company is reporting its earnings later today, which might reinforce its inclination not to comment.
Google revealed far more information about its Google Apps and Gmail outage last week. It has published a detailed incident report that cites the number of users affected, the root cause of the problem — misconfigured servers — and corrective measures.
Google also stores more historic data: Its App Status Dashboard goes back to two months. Apple's status page timeline goes back just two days.
But data about the performance of iCloud can be inferred from past complaints. An iCloud outage on Feb. 28 affected multiple iCloud services for about 3% of users over the course of several hours.
And the perception among some users is that iCloud disruptions are a common occurrence.
Dissatisfaction with iCloud isn't merely confined to the gripe-inclined. The Business Insider recently characterized iCloud's state as "calamitous." This sentiment was echoed in a recent article from The Verge. About the same time, Ars Technica published an article citing developer concerns about iCloud.
Nonetheless, Apple iCloud remains popular. It accounts for 27% of the total consumer media cloud storage usage in the U.S., putting it ahead of Dropbox and Google Play, research firm Strategy Analytics said last month.