Sometimes when starting ACT! and you are using TopLine Designer, you will get a message similar to this.

There was an error loading the metadata.
System.UnauthorizedAccessException: Access to the path 'xxx\Metadata.dna.xml' is denied.

This is caused by a Windows file security issue which means that you need to ensure that the user who is currently logged into Windows has access to the file that is given in the message.  You will need to navigate to the folder specified and right click on the Metadata.dna.xml file and choose Properties.  Then click on the Security tab and ensure that the current windows user has read permission to the file.  After you give the user permission to access the file, ACT! will start normally.  If you are unable to set the permissions, contact your network administrator as you may not have permission to modify the file attributes.