diff --git a/src/calibre/library/cli.py b/src/calibre/library/cli.py
index 0a392c1b8c..ea9f8a3f1e 100644
--- a/src/calibre/library/cli.py
+++ b/src/calibre/library/cli.py
@@ -386,7 +386,7 @@ def command_remove(args, dbpath):
         else:
             ids.append(int(y[0]))
 
-    do_remove(get_db(dbpath, opts), ids)
+    do_remove(get_db(dbpath, opts), set(ids))
 
     return 0
 
diff --git a/src/calibre/library/database2.py b/src/calibre/library/database2.py
index cdf1894ab6..79737f4f57 100644
--- a/src/calibre/library/database2.py
+++ b/src/calibre/library/database2.py
@@ -921,9 +921,12 @@ class LibraryDatabase2(LibraryDatabase):
         '''
         Removes book from the result cache and the underlying database.
         '''
-        path = os.path.join(self.library_path, self.path(id, index_is_id=True))
+        try:
+            path = os.path.join(self.library_path, self.path(id, index_is_id=True))
+        except:
+            path = None
         self.data.remove(id)
-        if os.path.exists(path):
+        if path and os.path.exists(path):
             try:
                 winshell.delete_file(path, no_confirm=True, silent=True)
             except: