After 2 weeks I synced my DashCore Wallet again and after sync 0 Dash is displayed.
Can someone tell me where my Dash is?
To understand, I've installed my DashCore Wallet on a Memory Stick.
are you sure you are loading the wallet file from your stick? In Dash Core, if you go to Tools > Information, where is your datadir located - on your USB stick, or somewhere else? If it is somewhere else, you need to either copy your wallet.dat from the stick to that location, or modify your wallet configuration file (Tools > Open Wallet Configuration File) to point at the USB stick.