The same problem
Owned for Galaxy SL almost in 18 months. Firstly, get stuck after 1 month used. Go to samsung service center and replacing with the new one, good after sales service. After that on the next 6 month, the same problem appear. Go to service center, and repair internal sd card with the new one, there's no cost since still under warranty. After analyze, the problem exist while download "Go Launcher" application. Currently still fine, while your not download similar applications. But in my opinion there's a bud or corruption at internal storage.