Hello Mark - The problem seems to be a file permission issue. I certainly have the Advanced Tools available. In the same piece, I am able to edit sound regions for some tracks and not for others. When I enter the audio editing mode through Command-6, the tools for 'change gain' and 'time and pitch machine', etc. are not available. However, for another track in the same project, they are available. The files that cause the problems are MP3 attachments that have been emailed to me. I did a 'get info' on the file to see if it was read only, but found that it was not locked and that I had permission to read and write. However, a minute ago, I noticed a little padlock symbol in the bottom right corner. I clicked it and now the file can be edited. The permissions listed in the 'get info' action did not change. Even more bizarre was that I went to another file that would not let me edit the audio, did not click the padlock on it, reloaded it, and now it is 'unlocked'; the same file in the same project that had been loaded earlier is still uneditable. Sounds like I've gone off the deep end.