Just wondered why this happened?
I'd like to give you an anwser, but I don't have one. I just know that sometimes things go wrong. Thankfully, it's very very rare. And when it happens, we have the automatic backups as well as the online backup (if you use that feature).
I closed the program and clicked on my database backup with the largest size 47kb dated 24 March 2014 and successfully loaded the file showing over 600 titles I own.
Was it the most recent backup? Did you lose some data (normally you shouldn't)?
Also, did you just click the backup, or did you use it to replace the default coollection file as explained here:http://www.coollector.com/help.html#backups