diff --git a/dlls/user32/class.c b/dlls/user32/class.c
index 2b2d07f8886..07d36f05d7d 100644
--- a/dlls/user32/class.c
+++ b/dlls/user32/class.c
@@ -1194,8 +1194,20 @@ INT WINAPI GetClassNameW( HWND hwnd, LPWSTR buffer, INT count )
     if (class == CLASS_OTHER_PROCESS)
     {
         WCHAR tmpbuf[MAX_ATOM_LEN + 1];
+        ATOM atom = 0;
 
-        ret = GlobalGetAtomNameW( GetClassLongW( hwnd, GCW_ATOM ), tmpbuf, MAX_ATOM_LEN + 1 );
+        SERVER_START_REQ( set_class_info )
+        {
+            req->window = wine_server_user_handle( hwnd );
+            req->flags = 0;
+            req->extra_offset = -1;
+            req->extra_size = 0;
+            if (!wine_server_call_err( req ))
+                atom = reply->base_atom;
+        }
+        SERVER_END_REQ;
+
+        ret = GlobalGetAtomNameW( atom, tmpbuf, MAX_ATOM_LEN + 1 );
         if (ret)
         {
             ret = min(count - 1, ret);
diff --git a/include/wine/server_protocol.h b/include/wine/server_protocol.h
index e4c2d923766..511ad5c6285 100644
--- a/include/wine/server_protocol.h
+++ b/include/wine/server_protocol.h
@@ -4525,11 +4525,13 @@ struct set_class_info_reply
 {
     struct reply_header __header;
     atom_t         old_atom;
+    atom_t         base_atom;
+    mod_handle_t   old_instance;
+    lparam_t       old_extra_value;
     unsigned int   old_style;
     int            old_extra;
     int            old_win_extra;
-    mod_handle_t   old_instance;
-    lparam_t       old_extra_value;
+    char __pad_44[4];
 };
 #define SET_CLASS_ATOM      0x0001
 #define SET_CLASS_STYLE     0x0002
@@ -6512,6 +6514,6 @@ union generic_reply
     struct terminate_job_reply terminate_job_reply;
 };
 
-#define SERVER_PROTOCOL_VERSION 554
+#define SERVER_PROTOCOL_VERSION 555
 
 #endif /* __WINE_WINE_SERVER_PROTOCOL_H */
diff --git a/server/class.c b/server/class.c
index d5f6712006a..6a7de7843e8 100644
--- a/server/class.c
+++ b/server/class.c
@@ -276,6 +276,7 @@ DECL_HANDLER(set_class_info)
     reply->old_extra     = class->nb_extra_bytes;
     reply->old_win_extra = class->win_extra;
     reply->old_instance  = class->instance;
+    reply->base_atom     = class->base_atom;
 
     if (req->flags & SET_CLASS_ATOM)
     {
diff --git a/server/protocol.def b/server/protocol.def
index c533f1b8eb3..5d89c2b3ba2 100644
--- a/server/protocol.def
+++ b/server/protocol.def
@@ -3179,11 +3179,12 @@ enum caret_state
     lparam_t       extra_value;    /* value to set in extra bytes */
 @REPLY
     atom_t         old_atom;       /* previous class atom */
+    atom_t         base_atom;      /* base class atom */
+    mod_handle_t   old_instance;   /* previous module instance */
+    lparam_t       old_extra_value; /* old value in extra bytes */
     unsigned int   old_style;      /* previous class style */
     int            old_extra;      /* previous number of class extra bytes */
     int            old_win_extra;  /* previous number of window extra bytes */
-    mod_handle_t   old_instance;   /* previous module instance */
-    lparam_t       old_extra_value; /* old value in extra bytes */
 @END
 #define SET_CLASS_ATOM      0x0001
 #define SET_CLASS_STYLE     0x0002
diff --git a/server/request.h b/server/request.h
index 8b823ba844b..10fd850ec1e 100644
--- a/server/request.h
+++ b/server/request.h
@@ -2056,12 +2056,13 @@ C_ASSERT( FIELD_OFFSET(struct set_class_info_request, extra_size) == 44 );
 C_ASSERT( FIELD_OFFSET(struct set_class_info_request, extra_value) == 48 );
 C_ASSERT( sizeof(struct set_class_info_request) == 56 );
 C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_atom) == 8 );
-C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_style) == 12 );
-C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_extra) == 16 );
-C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_win_extra) == 20 );
-C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_instance) == 24 );
-C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_extra_value) == 32 );
-C_ASSERT( sizeof(struct set_class_info_reply) == 40 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, base_atom) == 12 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_instance) == 16 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_extra_value) == 24 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_style) == 32 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_extra) == 36 );
+C_ASSERT( FIELD_OFFSET(struct set_class_info_reply, old_win_extra) == 40 );
+C_ASSERT( sizeof(struct set_class_info_reply) == 48 );
 C_ASSERT( FIELD_OFFSET(struct open_clipboard_request, window) == 12 );
 C_ASSERT( sizeof(struct open_clipboard_request) == 16 );
 C_ASSERT( FIELD_OFFSET(struct open_clipboard_reply, owner) == 8 );
diff --git a/server/trace.c b/server/trace.c
index c6020433f17..e6ed964e166 100644
--- a/server/trace.c
+++ b/server/trace.c
@@ -3795,11 +3795,12 @@ static void dump_set_class_info_request( const struct set_class_info_request *re
 static void dump_set_class_info_reply( const struct set_class_info_reply *req )
 {
     fprintf( stderr, " old_atom=%04x", req->old_atom );
+    fprintf( stderr, ", base_atom=%04x", req->base_atom );
+    dump_uint64( ", old_instance=", &req->old_instance );
+    dump_uint64( ", old_extra_value=", &req->old_extra_value );
     fprintf( stderr, ", old_style=%08x", req->old_style );
     fprintf( stderr, ", old_extra=%d", req->old_extra );
     fprintf( stderr, ", old_win_extra=%d", req->old_win_extra );
-    dump_uint64( ", old_instance=", &req->old_instance );
-    dump_uint64( ", old_extra_value=", &req->old_extra_value );
 }
 
 static void dump_open_clipboard_request( const struct open_clipboard_request *req )