diff --git a/beetsplug/thumbnails.py b/beetsplug/thumbnails.py
index ce3382fc8..6fd8c8cbe 100644
--- a/beetsplug/thumbnails.py
+++ b/beetsplug/thumbnails.py
@@ -39,8 +39,8 @@ from beets.util.artresizer import ArtResizer, has_IM, has_PIL
 
 
 BASE_DIR = os.path.join(BaseDirectory.xdg_cache_home, "thumbnails")
-NORMAL_DIR = os.path.join(BASE_DIR, "normal")
-LARGE_DIR = os.path.join(BASE_DIR, "large")
+NORMAL_DIR = util.bytestring_path(os.path.join(BASE_DIR, "normal"))
+LARGE_DIR = util.bytestring_path(os.path.join(BASE_DIR, "large"))
 
 
 class ThumbnailsPlugin(BeetsPlugin):
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 8b821174f..070dfeaf7 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -19,6 +19,7 @@ Fixes:
 * :doc:`plugins/fetchart`: Fix a bug where a database reference to a
   non-existent album art file would prevent the command from fetching new art.
   :bug:`1126`
+* :doc:`/plugins/thumbnails`: Fix a crash with Unicode paths. :bug:`1686`
 
 
 1.3.15 (October 17, 2015)