According to MacRumours there is a serious bug with the “Reset All Settings” option in iOS 8, causing users who activate the feature to lose all of their iWork documents stored in iCloud Drive.
Using the “Reset All Settings” option under General –> Reset has caused documents to be permanently deleted from iCloud Drive.
The “Reset All Settings” option explicitly says that “No data or media will be deleted,” which means that Apple was lying when it told users they were safe. It is meant to reset all user preferences to the default out-of-the-box settings not kill the documents.
MacRumours tested the bug and found that “Reset All Settings” deleted all iWork documents stored in iCloud Drive on the iPhone and on iCloud.com.
“After allowing time for syncing to a Mac running OS X Yosemite, all of the documents disappeared from that machine as well. Preview and TextEdit documents, which cannot be accessed on the iPhone, remained untouched on the Mac,” the magazine said.