diff --git a/TODO.md b/TODO.md
index 9e479832..251f1c91 100644
--- a/TODO.md
+++ b/TODO.md
@@ -4,7 +4,6 @@
 - highlight messages with mention
 - add room members loading indicator
 
-- fix media_mime
 - fix lag when clicking accounts in the AccountBar with a very long room list
 - fix: on startup, if a room's last event is a membership change,
   it won't be visible in timeline no matter what the user config is
diff --git a/src/backend/nio_callbacks.py b/src/backend/nio_callbacks.py
index 05d9d484..fbf904df 100644
--- a/src/backend/nio_callbacks.py
+++ b/src/backend/nio_callbacks.py
@@ -149,7 +149,7 @@ class NioCallbacks:
             media_height     = info.get("h") or 0,
             media_duration   = info.get("duration") or 0,
             media_size       = info.get("size") or 0,
-            media_mime       = info.get("mimetype") or 0,
+            media_mime       = info.get("mimetype") or "",
             media_crypt_dict = media_crypt_dict,
 
             thumbnail_url =