diff --git a/aiidalab_launch/profile.py b/aiidalab_launch/profile.py
index b555258..e22318e 100644
--- a/aiidalab_launch/profile.py
+++ b/aiidalab_launch/profile.py
@@ -88,7 +88,7 @@ def __post_init__(self):
 
         # Normalize extra mount mode to be "rw" by default
         # so that we match Docker default but are explicit.
-        for extra_mount in self.extra_mounts:
+        for extra_mount in self.extra_mounts.copy():
             self.parse_extra_mount(extra_mount)
             if len(extra_mount.split(":")) == 2:
                 self.extra_mounts.remove(extra_mount)