Headline News: SD cards have NOT stopped working - but some methods that apps used to use will no longer work.
Back when Honeycomb was released, Google introduced a new method of accessing SD cards, which was largely ignored at the time, but is now being implemented by Samsung (and maybe by other manufacturers who have devices with MicroSD card slots). There's a long Android Police article about it, but here's the TL;DR version.
- Every app still has read access to every file on your SD card.
- Every app can still write to your SD card, but it will have to use one of the new methods. Simply having write access to the card won't work any more.
- You do NOT need to root your device to regain write access to your SD card.
Apps can use the following methods to gain write access to your SD card:
- A private folder, which is created programmatically by the app, and will be named according the app's package name, e.g. Android/data/com.example.foo (to steal Android Police's example). This is appropriate for apps which download and otherwise manipulate files on your behalf, without you ever knowing or needing to know their filenames or location (e.g. podcatchers).
NB: If you uninstall the app, this folder and all the files in it will automatically be removed from your card
- Use the Storage Access Framework. This is appropriate for apps that use a file picker to allow you to open / edit a particular file (e.g. document editors).
- MTP (Media Transfer Protocol) which has historically (well, recently,) more commonly been used by PCs (rather than apps on the device itself) to transfer and manipulate files when your device is attached to a PC as a mass storage device. Anecdotally, it does seem to be slightly unreliable in some cases. This is appropriate for apps that mass-manipulate general files and folders under user control, such as file managers.
Apps that have been updated / do work
- BeyondPod 3.3.68 / 3.30.68 onwards (private folder)
Apps that don't yet work (can read, but not write/delete)
- MX Player