diff --git a/sipsimple/account/xcap/storage/file.py b/sipsimple/account/xcap/storage/file.py
index b2850b15..10ae04c5 100644
--- a/sipsimple/account/xcap/storage/file.py
+++ b/sipsimple/account/xcap/storage/file.py
@@ -1,87 +1,90 @@
 
 """XCAP backend for storing data in files"""
 
 __all__ = ["FileStorage"]
 
 import errno
 import os
 import platform
 import random
 
 from application.system import makedirs, openfile, unlink
 from zope.interface import implementer
 
 from sipsimple.account.xcap.storage import IXCAPStorage, XCAPStorageError
 
 
 @implementer(IXCAPStorage)
 class FileStorage(object):
     """Implementation of an XCAP backend that stores data in files."""
 
 
     def __init__(self, directory, account_id):
         """Initialize the storage for the specified directory and account ID"""
         self.directory = directory
         self.account_id = account_id
         self.names = set()
 
     def load(self, name):
         """Read the file given by name and return its content."""
         try:
             document = open(os.path.join(self.directory, self.account_id, name), 'rb').read()
         except (IOError, OSError, UnicodeDecodeError) as e:
             raise XCAPStorageError("failed to load XCAP data for %s/%s: %s" % (self.account_id, name, str(e)))
         else:
             self.names.add(name)
             return document
 
     def save(self, name, data):
         """Write the data in a file identified by name."""
         filename = os.path.join(self.directory, self.account_id, name)
         tmp_filename = '%s.%d.%08X' % (filename, os.getpid(), random.getrandbits(32))
         try:
             makedirs(os.path.join(self.directory, self.account_id))
             file = openfile(tmp_filename, 'wb', permissions=0o600)
             file.write(data if isinstance(data, bytes) else data.encode())
             file.close()
             if platform.system() == 'Windows':
                 # os.rename does not work on Windows if the destination file already exists.
                 # It seems there is no atomic way to do this on Windows.
                 unlink(filename)
             os.rename(tmp_filename, filename)
         except (IOError, OSError) as e:
             raise XCAPStorageError("failed to save XCAP data for %s/%s: %s" % (self.account_id, name, str(e)))
         else:
             self.names.add(name)
 
     def delete(self, name):
         """Delete the data stored in the file identified by name"""
         try:
             os.unlink(os.path.join(self.directory, self.account_id, name))
         except OSError as e:
             if e.errno == errno.ENOENT:
                 self.names.discard(name)
                 return
             raise XCAPStorageError("failed to delete XCAP data for %s/%s: %s" % (self.account_id, name, str(e)))
         else:
-            self.names.remove(name)
+            try:
+                self.names.remove(name)
+            except KeyError:
+                pass
 
     def purge(self):
         """Delete all the files stored by the backend"""
         failed = []
         for name in self.names:
             try:
                 os.unlink(os.path.join(self.directory, self.account_id, name))
             except OSError as e:
                 if e.errno == errno.ENOENT:
                     continue
                 failed.append(name)
         self.names.clear()
         try:
             os.rmdir(os.path.join(self.directory, self.account_id))
         except OSError:
             pass
         if failed:
             raise XCAPStorageError("the following files could not be deleted for %s: %s" % (self.account_id, ', '.join(failed)))