The only annoying thing I experience is that the cover art will unload on the side-loaded books where you just get the generic cover with the text of the book. But once you click the book it loads the artwork, which seems to last a few days before quickly going back to the generic cover. But the book itself never leaves the device. I can't say I have experienced this ever (except for once, mentioned below) and I have over 150 books on my 32Gb device.
Just some random thoughts I am wondering:
- Is it an ads-supported model (mine isn't)
- Are the books in a broken-DRM .mobi? Not judging, i've done it too, just curious if Amazon has some sort of "signature" in mobis that allow it to detect a book that had DRM removed?
- Are they standard .epub?
- What is the size of the device? (Maybe smaller 8Gb devices will clean up and prioritize non-Kindle content to make way for "official content)
- Which device is it? (Scribe, Oasis, Paperwhite, older paperwhite, etc)
The one time I had it deleting my book was a large book (it was 400Mb) and it was on an older 8Gb paperwhite. I still had PLENTY of storage space available (I was using around 4Gb) but it kept deleting that book. This was the only time I have seen it happen and it was with this one specific book. That was many years ago and I haven't seen it since. That book was a DRM-removed book I got through "shared" means. Which has led me to question if the Kindle removes it because it could detect that the DRM had been removed or because of its large size. But this was a one-off experience for me. The book was readable by the device. It would download for several weeks at a time before being removed. You could redownload it and it would work for weeks again before dissapearing. I never could figure it out.
*Edit to add: I believe the kindle won't delete epubs you sideload via the Amazon kindle email gateway, but I have no interest in doing that.
These days it wants ePub only, but things also seem to "just work", and I always assumed it's because they added support for it on device side. What are the issues that you ran into?
Fortunately, getting two units in a row with jarring pink blotches was enough of a non-starter to suggest that she just revert to a V4 without my having to explain the confusing behavior.
I've side-loaded .mobi and .pdf files, and have never had anything disappear, whilst still buying some things from Amazon kindle store...