Hi Emma, In order to get the key, you need to have access to a desktop browser already synched to your account. If this is the case, you can get it on the Sync tab within the Options (Preferences if you are running in Mac Os X) menu. In this window, if Sync is properly configured, you should see a drop down menu where you can select "My Sync Key" to get it. Take in count that we don't store your Sync Key so if you don't have it we are not going to be able to provide you a new one without restoring your encrypted data. I hope you can solve the issue with this information.