[Zubersoft]

Thanks for linking the post Andy. Colin - the main problem is that there is no historical knowledge about deleted objects. So when a two-way sync is performed and one device has something the other doesn't, the app can't know which path to take - create that object so it exists on both, or delete it so it exists on neither. So it chooses the safe path. If you enable "Prompt user for decision", you can have complete control over the sync and choose how to handle each conflict. 

Other sync services most likely have historical information about deleted objects (and a file system is actually simpler because you can uniquely identify every file with a path). While I could add something like this to the database, it would certainly add another layer of complexity during the sync and would increase the size of the database over time for little gain (for most users).  There is also the problem that if multiple libraries are involved in the sync that didn't start out with identical databases, all of the songs can have different database ids, and identifying matching songs is not guaranteed to be 100% accurate in every case (there are some pretty complex cases I've encountered with many songs with matching titles and matching files). 

I'm open to suggestions and ideas to find a way to better deal with these problems. Without historical information about deletions, I'm just not sure if there is any kind satisfactory solution.

Thanks,
Mike