user10371: Installed the Bitcoin QT client only last week... synchronised it with the blockchain... and sent my bitcoins to this adress...
Now, when I want to send to some other address, it asks for the passphrase. However, have never had the option of providing a passphrase. Any thoughts on this?

user9790: 
However, have never had the option of providing a passphrase. 

You must certainly have set a passphrase in the past. There's no way to remove it without knowing exactly what it is. If you can not recall what password you set, your funds are lost. 

10371: <p>Installed the Bitcoin QT client only last week... synchronised it with the blockchain... and sent my bitcoins to this adress...
Now, when I want to send to some other address, it asks for the passphrase. However, have never had the option of providing a passphrase. Any thoughts on this?</p>
 9790: <blockquote>
  <p>However, have never had the option of providing a passphrase. </p>
</blockquote>

<p>You must certainly have set a passphrase in the past. There's no way to remove it without knowing exactly what it is. If you can not recall what password you set, your funds are lost. </p>
