[quote="jradams1955"I thought I had it on my last save, but it will not let me open the file[/quote]
Click the menu "Help->Locate the automatic backups", then close Coollector (otherwise you won't be able to test the files, because there can only be one instance of the program running at a time).
When you've located the best backup, here is how to replace your current file with it:
http://www.coollector.com/help.html#backupsPlease tell me if you have any problem.