Dropbox said on Sunday it was making progress in restoring service after the popular file storage service went offline on Friday.
As of Sunday afternoon Pacific time, the service said more than 99 percent of users can access their files. But five percent of users were having trouble syncing files from the desktop client, and about 20 percent were having issues with Dropbox's mobile applications.
"Within a few hours, well be rolling out a change that will further improve things for those users," according to a blog post.
Dropbox dismissed claims on Friday that it had been hacked and attributed the problems to "routine internal maintenance."
One of the issues revolved around photos. It disabled photo sharing and turned off a "Photos" tab on dropbox.com. Photos were still available through the desktop client and the "Files" tab on dropbox.com, it said.
The Photos tab remained disabled on Sunday. "Were continuing to make a lot of progress restoring full service to all users, and are doing so in careful steps," it said.
Service outages and probes by cyberattackers are some of the biggest concerns for users of cloud-based services.
Dropbox saves a history of all deleted and earlier versions of files for 30 days for all accounts. The service uses Amazon's S3 (Simple Storage Service) to hold encrypted versions of people's files, according to its website.
Founded in 2007, Dropbox says it has 200 million users worldwide.
Send news tips and comments to jeremy_kirk@idg.com. Follow me on Twitter: @jeremy_kirk