Don't name an Ardour track/bus 'click'
Or it won't load again. I ran into this the hard way, it is a documented bug: http://tracker.ardour.org/view.php?id=2234 Newer versions may have fixed it, but beware. I experienced this on 2.4.1 rev 3243. I was able to fix it, however. Since the filename.ardour is XML, it's easy to edit it. I looked through the filename.ardour and did a search and replace on 'click' and changed it to 'clickk'. BE AWARE however, that there is a section named Click ----- stuff goes here ----- /Click that you should NOT change, nor change anything inside it. That is for the actual click track. Now, inside /interchange/projectname/audiofiles will be a lot of little pieces of audio. There will be one (or several) in there named click-1.wav, click-2.wav, etc. Carefully rename them all to 'clickk' or whatever you are renaming it to. Keep the -1 or -2 part of the filename, just rename the 'click' part. Now in the directory named 'peaks' will be another file, click-2%A.peak that should be renamed 'clickk-2%A.peak as well. I then loaded it, and everything worked fine! Scary, since I had just spent 5 hours tracking someone else playing, I was otherwise faced with losing it all.