I have the same problem with Strawberry version 0.9.3 on Windows 10:
My Subsonic-Server is connected and a lot of music is synced. But since recently, when I hit the "refresh library"-Button (German: Bibliothek erneuern), it says it is receiving songs for 1681 albums and gets stuck at 99%. After canceling the process, the library is again not up-to-date.
Does anyone have an idea how I can figure out why this happens?