it seems as if it has been fixed just recently.
[quote]Fixed in build 669

It was caused by following situation:
1. Install MMA 1.2.0
2. Go to Library Folders and remove /Music folder
3. Go to sync settings in MMA (/Music folder will be automatically re-added)
4. Update to MMA 1.3.0
5. Sometimes /Music sync folder was not correctly migrated from 1.2.0 to 1.3.0 and was removed from Library - including all tracks

That is the usecase that should be tested mainly. But a refactor was needed so other parts of Library folders management should be tested too.
[/quote]

Hi,
Based on log it looks like we know what is going on and is tracked as http://www.ventismedia.com/mantis/view.php?id=13525

My app frequently loses the library when i open the app by clicking on the widget.
Log ID: WXNS366I7Q

Happens in like 1 of 1000 clicks on the widget. I am not even sure if it is the cause but I had this correlation.
Case: A song is already playing and i want to give some stars therefore I click on the widget and bam. mediamonkey stops playing the song and says no media.