[Siavahda]

I used Calibre to send two mobi files to my Kindle Paperwhite, and the books show up when I disconnect my Kindle. But after a few minutes, hours, or overnight (I have been trying to solve this on my own for almost a week) the two books vanish. Calibre still insists they are present on the device, and if I open up the directory, the files are definitely there, but the Kindle itself keeps vanishing them.

They don't vanish if I convert the mobi files to azw3, but for formatting reasons I don't want to do that unless I really have to. Also, in azw3 format, the Kindle seems to think the files have no covers, if that's relevant.

The files were originally in ePub format, which I converted to mobi with Calibre. Following advice from other threads, I reconverted the files and then converted mobi-->mobi. I thought this had fixed the problem until the books vanished again this morning. Restarting the Kindle hasn't helped. I have tried deleting all the indexing files for these books before re-sending the files to the device, but that hasn't fixed it either.

Can anyone help? Why does my Kindle keep disappearing these files?