diff --git a/OpenChange/MAPIStoreFallbackContext.m b/OpenChange/MAPIStoreFallbackContext.m
index 41463542a..5b1a40ad1 100644
--- a/OpenChange/MAPIStoreFallbackContext.m
+++ b/OpenChange/MAPIStoreFallbackContext.m
@@ -55,7 +55,10 @@
   NSString *baseURL, *url, *name;
   MAPIStoreUserContext *userContext;
 
-  baseURL = [NSString stringWithFormat: @"sogo://%@@fallback/", userName];
+  baseURL = [NSString stringWithFormat: @"sogo://%@@fallback/",
+                      [userName stringByReplacingOccurrencesOfString: @"@"
+                                withString: @"%40"]];
+
 
   context = talloc_zero (memCtx, struct mapistore_contexts_list);
   context->url = [baseURL asUnicodeInMemCtx: context];
@@ -99,7 +102,10 @@
                           forUser: (NSString *) userName
 {
   return [NSString stringWithFormat: @"sogo://%@@fallback/0x%.16"PRIx64"/",
-                   userName, (unsigned long long) fid];
+                   [userName stringByReplacingOccurrencesOfString: @"@"
+                             withString: @"%40"],
+                   (unsigned long long) fid];
+
 }
 
 @end
diff --git a/OpenChange/MAPIStoreGCSBaseContext.m b/OpenChange/MAPIStoreGCSBaseContext.m
index 216eab01c..384859c5d 100644
--- a/OpenChange/MAPIStoreGCSBaseContext.m
+++ b/OpenChange/MAPIStoreGCSBaseContext.m
@@ -82,7 +82,9 @@
                                                    andTDBIndexing: indexing];
       parentFolder = [[userContext rootFolders] objectForKey: moduleName];
       baseUrl = [NSString stringWithFormat: @"sogo://%@@%@/",
-                          userName, moduleName];
+                          [userName stringByReplacingOccurrencesOfString: @"@"
+                                    withString: @"%40"],
+                          moduleName];
 
       subfolders = [parentFolder subFolders];
       max = [subfolders count];
@@ -127,7 +129,9 @@
   if (![parentFolder newFolderWithName: folderName
                        nameInContainer: &nameInContainer])
     mapistoreURI = [NSString stringWithFormat: @"sogo://%@@%@/%@/",
-                             userName, moduleName, nameInContainer];
+                             [userName stringByReplacingOccurrencesOfString: @"@"
+                                       withString: @"%40"],
+                             moduleName, nameInContainer];
   else
     mapistoreURI = nil;
   [MAPIApp setUserContext: nil];
diff --git a/OpenChange/MAPIStoreMailContext.m b/OpenChange/MAPIStoreMailContext.m
index 0cddee582..87493ff09 100644
--- a/OpenChange/MAPIStoreMailContext.m
+++ b/OpenChange/MAPIStoreMailContext.m
@@ -126,7 +126,11 @@ MakeDisplayFolderName (NSString *folderName)
   trashName = [NSString stringWithFormat: @"folder%@",
                        [unprefixedFolders componentsJoinedByString: @"/folder"]];
 
-  urlBase = [NSString stringWithFormat: @"sogo://%@:%@@mail/", userName, userName];
+  urlBase = [NSString stringWithFormat: @"sogo://%@:%@@mail/",
+                      [userName stringByReplacingOccurrencesOfString: @"@"
+                                withString: @"%40"],
+                      [userName stringByReplacingOccurrencesOfString: @"@"
+                                withString: @"%40"]];
   for (count = 0; count < 3; count++)
     {
       context = talloc_zero (memCtx, struct mapistore_contexts_list);
@@ -199,7 +203,10 @@ MakeDisplayFolderName (NSString *folderName)
                                  inContainer: accountFolder];
   if ([newFolder create])
     mapistoreURI = [NSString stringWithFormat: @"sogo://%@:%@@mail/%@/",
-                             userName, userName,
+                             [userName stringByReplacingOccurrencesOfString: @"@"
+                                       withString: @"%40"],
+                             [userName stringByReplacingOccurrencesOfString: @"@"
+                                       withString: @"%40"],
                              [[folderName stringByEncodingImap4FolderName] stringByAddingPercentEscapesUsingEncoding: NSUTF8StringEncoding]];
   else
     mapistoreURI = nil;
@@ -275,8 +282,12 @@ MakeDisplayFolderName (NSString *folderName)
                         componentsSeparatedByString: @"/"];
   folderName = [NSString stringWithFormat: @"folder%@",
                          [unprefixedFolders componentsJoinedByString: @"/folder"]];
-  url = [NSString stringWithFormat: @"sogo://%@:%@@outbox/%@", userName,
-                  userName, folderName];
+  url = [NSString stringWithFormat: @"sogo://%@:%@@outbox/%@",
+                  [userName stringByReplacingOccurrencesOfString: @"@"
+                            withString: @"%40"],
+                  [userName stringByReplacingOccurrencesOfString: @"@"
+                            withString: @"%40"],
+                  folderName];
 
   context = talloc_zero (memCtx, struct mapistore_contexts_list);
   context->url = [url asUnicodeInMemCtx: context];
diff --git a/OpenChange/MAPIStoreNotesContext.m b/OpenChange/MAPIStoreNotesContext.m
index 594a819b5..725b0d158 100644
--- a/OpenChange/MAPIStoreNotesContext.m
+++ b/OpenChange/MAPIStoreNotesContext.m
@@ -45,7 +45,8 @@
 
   context = talloc_zero(memCtx, struct mapistore_contexts_list);
   context->url = talloc_asprintf (context, "sogo://%s@notes/",
-                                  [userName UTF8String]);
+                                  [[userName stringByReplacingOccurrencesOfString: @"@"
+                                             withString: @"%40"] UTF8String]);
   // context->name = "Notes personnelles";
   context->main_folder = true;
   context->role = MAPISTORE_NOTES_ROLE;
diff --git a/OpenChange/MAPIStoreSOGo.m b/OpenChange/MAPIStoreSOGo.m
index 923541764..56d9cd4d0 100644
--- a/OpenChange/MAPIStoreSOGo.m
+++ b/OpenChange/MAPIStoreSOGo.m
@@ -1693,7 +1693,10 @@ sogo_manager_generate_uri (TALLOC_CTX *mem_ctx,
       username = [NSString stringWithUTF8String: (user ? user : "*")];
       /* Do proper directory lookup here */
       directory = [NSString stringWithUTF8String: (folder ? folder : "*")];
-      partialURLString = [NSString stringWithFormat: @"sogo://%@:*@%@", username, directory];
+      partialURLString = [NSString stringWithFormat: @"sogo://%@:*@%@",
+                                   [username stringByReplacingOccurrencesOfString: @"@"
+                                             withString: @"%40"],
+                                   directory];
     }
   if (![partialURLString hasSuffix: @"/"])
     partialURLString = [partialURLString stringByAppendingString: @"/"];