Logg:
[2018-04-23 17:33:04 CEST] WARN CoverArtController Failed to process cover art \\MYBOOKLIVE\Public\-=MUSIK=-\Bullet\Dust To Gold [2018]\07-Wildfire.mp3: java.lang.NoClassDefFoundError: Could not initialize class sun.java2d.Disposer
[2018-04-23 17:33:04 CEST] WARN CoverArtController Failed to create thumbnail for Media file 39564 - Rogue Soldier
Feels like it could be after the latest Windows Java update (version 8, update 171).
Never had this problem before...