IMPORTANT: SD cards and Android 4.4 (KitKat)
: Unfortunately with Android 4.4, Google has made using SD cards very difficult. For a variety of reasons, such as preventing one app from tampering with another app's data, the SD card has in effect become "read only" for all folders except for one specific folder per app. If you click here to do a google search for kitkat sd card support
you'll find lots of posts discussing this, and explaining the pros and cons of Google's decision.
The result is that is is difficult for you to put your CC library on your SD card. The only folder CC can write on the SD card is a temporary files folder that gets deleted when you delete the associated app. In plain words, that means a) there is only one folder on the SD card where CC can store your library, and b) that your library would be deleted from your SD card if you ever uninstalled Calibre Companion or cleared its data.
If you upgraded to KitKat and your library is on an SD card then there are two ways to recover from Google's change:
- You can root your device and remove the restriction. Not something we'd recommend or can support.
- You can move your library to your phone's internal memory, and it will then work as before. See the answer How do I change the folder on my device where the books are stored? for how to move your library.
We are still considering whether or not to allow CC to put libraries inside the temporary files folder on the SD card to which CC can write. The fact that the library can be automatically deleted by Android is a very large disincentive. It also is not clear whether reading apps would have difficulties because they could not create temporary files in that folder.
If you are running a version of Android less than 4.4, you can still put your library on an SD card, although you might not want to do that if your device is susceptible to being upgraded to KitKat. See the answer How do I change the folder on my device where the books are stored?
. Using SD cards is explained at the end of the answer.