The mysterious case of some Kindles losing sideloaded content
Here is something that has been affecting many a Kindle user though strangely not as wide-spread for everyone to make a hue and cry on it. Maybe that is also the reason why we haven’t seen Amazon reacting to the same as well. It is about Kindle devices losing all sideloaded content under some unknown mysterious circumstances. It is not known for sure what could be causing it though many claim it might have something to do with the airplane mode kept on for a prolonged period of time.
Also, those who have encountered the issue seem to agree on one aspect, that they used Calibre to sideload the content. However, once the airplane mode is turned off, all sideloaded content seems to vanish. So, going by that trend, the only remedy to the issue that seems to be viable at the moment is to switch off airplane mode on your Kindle once in a while. It might be worth checking if this does the trick.
Interestingly, Amazon has been releasing a barrage of software updates but none seem to address this particular issue. Maybe not using USB to sideload content to your Kindle might be another way to avert the situation. As a Reddit user stated, you can opt for the Send-to-Kindle option instead though it is not known if this is a failsafe method of preventing the Kindle from losing all sideloaded content once it goes online.
Those affected by the issue will also do good to send their feedback to Amazon. Right now, this is the best that users can do as they are more likely to react to it once they see a sizeable portion of Kindle users have been affected by the bug.