Google applications including YouTube, email and Docs have suffered a rare service outage, with users unable to access many of the company's services.
The outage started shortly before noon UK time, lasting more than half an hour before services were restored.
Users around the world reported problems with Gmail, Google Drive, the Android Play Store, Maps and more.
Google's search engine, however, remained unaffected by the problems affecting its other services.
Google said the problem hit its authentication system, which is used for logging in and similar functions, and lasted about 45 minutes.
Users were still able to access the websites' landing pages in "incognito mode", which does not store a log of the users' browsing activity.
Today, at 3.47AM PT Google experienced an authentication system outage for approximately 45 minutes due to an internal storage quota issue. This was resolved at 4:32AM PT, and all services are now restored.— Google Cloud (@googlecloud) December 14, 2020
The brief outage had a significant impact on the company's millions of users, many of whom rely on Google services for basic work apps such as email and calendars.
Users of Google Docs could continue to work if they had synced documents offline but were unable to use any online features.
The outage also affected Google-connected smart devices such as Home speakers - leading some users to complain on social media of being unable to switch off some lights in their homes.
I’m sitting here in the dark in my toddler’s room because the light is controlled by @Google Home. Rethinking... a lot right now.— Joe Brown (@joemfbrown) December 14, 2020
It also had a knock-on effect on other apps, with players of the smartphone game Pokémon Go, for example, reporting being unable to log in.
Despite the widespread outage, Google's service dashboard initially showed no errors - before switching to red status across all services.
"We're aware of a problem with Gmail affecting a majority of users. The affected users are unable to access Gmail," the statement said, with the word "Gmail" replaced by other services.
The Google crisis may have been brief - it took services offline for less than an hour - but it was an unnerving reminder of just how dependent millions of people have become on services in the cloud.
Anyone who tried to open a Google Document or respond to an urgent Gmail message will have felt a sense of dread when the message came back: "Please try reloading this page, or coming back to it in a few minutes. We're sorry for the inconvenience."
The pandemic has shown us just how valuable services like the Google Cloud Platform can be to keep a workforce collaborating productively from home.
But the businesses that have opted for Google's Cloud will have been troubled by today's incident - however brief. They will want to know exactly what went wrong and to get assurances that it won't happen again.
"All services are now restored," Google said in a statement.
"We apologise to everyone affected, and we will conduct a thorough follow-up review to ensure this problem cannot recur in the future."
Such failures in Google's systems are rare, though a problem with some servers caused difficulties for US users in June 2019.
In that instance, the culprit was a change to server settings that was supposed to have been applied to a few machines in a specific region but was accidentally applied to many more.