Because new @transactions have been recorded on the @blockchain from the last time you opened your wallet, which needs to scan all of them to make sure non of those transaction is yours. This process is not necessary in a mymonero-style (openmonero) wallet, a central server (which could be managed by you) does this work for you.
Fordi nye @transaktioner er blevet gemt på @blockchainen siden du åbnede din tegnebog sidst, skal alle transaktioner skannes for være sikker på at ingen af transaktionerne er dine. Denne process er ikke nødvendig i en tegnebog i stil med mymonero (openmonero), en central server (som kan styres af dig) gør dette arbejde for dig.