The cloud storage industry was dealt yet another blow over the weekend as Dropbox revealed that some of its users may have lost files as a result of a glitch when using a feature called Selective Sync.

As the name suggests, Selective Sync allows a Dropbox user to select only the folders they want to be synced to their computer. A bug in an older version of Dropbox for desktop users, however, led to some files being deleted when the desktop application shut down or restarted while Selective Sync was active.

Dropbox said they’ve patched the desktop client so the issue is no longer present. What’s more, they’ve made sure all users are running an updated version of the client and have retired all affected versions so they can no longer be used. The company also said they’re putting further emphasis on their testing procedures to make sure it doesn’t happen again.

Affected members are being offered a free year of Dropbox Pro ($9.99 per month or $99 annually) which includes up to 1TB of storage space.

Unfortunately for some, the damage has already been done and some files are inevitably gone. It’s events like these that highlight the importance of having multiple backups.

Over the summer, my main storage drive died at a very inopportune time but thankfully, I had nearly everything backed up on two separate drives (one of which is stored in a fireproof safe). Ideally, you’d even want a copy of critical data stored off-site but given concerns over privacy, I can understand why some would be hesitant to use cloud storage.