Online information storage firm Evernote has asked all users to reset their passwords following a security breach by hackers.
The California-based company, which allows people to store and organise personal data on an external server, is thought to have about 50 million users, the BBC reports.
It says user names, email addresses and encrypted passwords were accessed, but is insisting no payment details or stored content were accessed, changed or lost.
Evernote acts like an online personal organiser, with users able to save data such as video clips, images, web pages, notes and itineraries in an external storage system commonly known as the cloud.
In February, Apple revealed a "small number" of its computers had been hacked, but added there was no sign of data theft.
The hack came a week after social-networking firm Facebook said it had traced a cyber-attack back to China after some of its employee laptops were hacked.
A month ago, micro-blogging website Twitter announced it had been the victim of a security breach which compromised the accounts of 250,000 users.
