When you insert a storage card that has not been used on HTC Desire 550 before, the card will be mounted as removable storage by default.
If the storage card is new or doesn't have content you want to keep, you can format the storage card to use it as internal storage for HTC Desire 550
Home screen, tap
- Under Removable storage, tap next to the storage card name.
- Tap .
- Follow the onscreen instructions to move your installed apps and their data from the phone storage to the storage card.