Dropbox said 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 5 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.