diff --git a/src/command/cmd_funcs.c b/src/command/cmd_funcs.c
index 107b1caf8..05d032274 100644
--- a/src/command/cmd_funcs.c
+++ b/src/command/cmd_funcs.c
@@ -57,6 +57,7 @@
 #include "plugins/plugins.h"
 #include "ui/inputwin.h"
 #include "ui/ui.h"
+#include "ui/window.h"
 #include "ui/window_list.h"
 #include "xmpp/avatar.h"
 #include "xmpp/chat_session.h"
@@ -8456,6 +8457,7 @@ cmd_omemo_start(ProfWin* window, const char* const command, gchar** args)
         win_println((ProfWin*)chatwin, THEME_DEFAULT, "!", "Initiating OMEMO session with %s...", chatwin->barejid);
         omemo_start_session(chatwin->barejid);
         chatwin->is_omemo = TRUE;
+        win_clear_warned_jids((ProfWin*)chatwin);
     } else if (window->type == WIN_MUC) {
         ProfMucWin* mucwin = (ProfMucWin*)window;
         assert(mucwin->memcheck == PROFMUCWIN_MEMCHECK);
@@ -8471,6 +8473,7 @@ cmd_omemo_start(ProfWin* window, const char* const command, gchar** args)
             win_println((ProfWin*)mucwin, THEME_DEFAULT, "!", "Initiating OMEMO session in %s...", mucwin->roomjid);
             omemo_start_muc_sessions(mucwin->roomjid);
             mucwin->is_omemo = TRUE;
+            win_clear_warned_jids((ProfWin*)mucwin);
         } else {
             win_println(window, THEME_DEFAULT, "!", "MUC must be non-anonymous (i.e. be configured to present real jid to anyone) and members-only in order to support OMEMO.");
         }
@@ -8589,6 +8592,7 @@ cmd_omemo_end(ProfWin* window, const char* const command, gchar** args)
 
         chatwin->is_omemo = FALSE;
         accounts_add_omemo_state(session_get_account_name(), chatwin->barejid, FALSE);
+        win_clear_warned_jids((ProfWin*)chatwin);
     } else if (window->type == WIN_MUC) {
         ProfMucWin* mucwin = (ProfMucWin*)window;
         assert(mucwin->memcheck == PROFMUCWIN_MEMCHECK);
@@ -8600,6 +8604,7 @@ cmd_omemo_end(ProfWin* window, const char* const command, gchar** args)
 
         mucwin->is_omemo = FALSE;
         accounts_add_omemo_state(session_get_account_name(), mucwin->roomjid, FALSE);
+        win_clear_warned_jids((ProfWin*)mucwin);
     } else {
         win_println(window, THEME_DEFAULT, "-", "You must be in a regular chat window to start an OMEMO session.");
         return TRUE;
diff --git a/src/omemo/omemo.c b/src/omemo/omemo.c
index bfd984a33..dd6e60f2f 100644
--- a/src/omemo/omemo.c
+++ b/src/omemo/omemo.c
@@ -30,6 +30,7 @@
 #include "omemo/omemo.h"
 #include "omemo/store.h"
 #include "ui/ui.h"
+#include "ui/window.h"
 #include "ui/window_list.h"
 #include "xmpp/connection.h"
 #include "xmpp/muc.h"
@@ -514,18 +515,21 @@ omemo_set_device_list(const char* const from, GList* device_list)
             }
 
             if (!found) {
-                if (equals_our_barejid(jid->barejid)) {
-                    if (dev_id != omemo_ctx.device_id) {
-                        cons_show("New OMEMO device (ID: %u) added to your account.", dev_id);
-                    }
-                } else {
-                    ProfChatWin* chatwin = wins_get_chat(jid->barejid);
-                    if (chatwin) {
-                        win_println((ProfWin*)chatwin, THEME_DEFAULT, "!", "New OMEMO device (ID: %u) found for %s.", dev_id, jid->barejid);
+                auto_gchar gchar* dev_id_str = g_strdup_printf("%u", dev_id);
+                if (!g_key_file_has_key(omemo_ctx.knowndevices.keyfile, jid->barejid, dev_id_str, NULL)) {
+                    if (equals_our_barejid(jid->barejid)) {
+                        if (dev_id != omemo_ctx.device_id) {
+                            cons_show("New OMEMO device (ID: %u) added to your account.", dev_id);
+                        }
                     } else {
-                        ProfMucWin* mucwin = wins_get_muc(jid->barejid);
-                        if (mucwin) {
-                            win_println((ProfWin*)mucwin, THEME_DEFAULT, "!", "New OMEMO device (ID: %u) found for %s.", dev_id, jid->barejid);
+                        ProfChatWin* chatwin = wins_get_chat(jid->barejid);
+                        if (chatwin) {
+                            win_println((ProfWin*)chatwin, THEME_DEFAULT, "!", "New OMEMO device (ID: %u) found for %s.", dev_id, jid->barejid);
+                        } else {
+                            ProfMucWin* mucwin = wins_get_muc(jid->barejid);
+                            if (mucwin) {
+                                win_println((ProfWin*)mucwin, THEME_DEFAULT, "!", "New OMEMO device (ID: %u) found for %s.", dev_id, jid->barejid);
+                            }
                         }
                     }
                 }
@@ -728,17 +732,6 @@ omemo_start_device_session(const char* const jid, uint32_t device_id,
         }
     } else {
         log_debug("[OMEMO] session with %s device %d exists", jid, device_id);
-        if (omemo_ctx.notifying) {
-            ProfChatWin* chatwin = wins_get_chat(jid);
-            if (chatwin) {
-                win_println((ProfWin*)chatwin, THEME_DEFAULT, "!", "OMEMO session with %s (device %u) already exists.", jid, device_id);
-            } else {
-                ProfMucWin* mucwin = wins_get_muc(jid);
-                if (mucwin) {
-                    win_println((ProfWin*)mucwin, THEME_DEFAULT, "!", "OMEMO session with %s (device %u) already exists.", jid, device_id);
-                }
-            }
-        }
     }
 
 out:
@@ -822,7 +815,11 @@ omemo_on_message_send(ProfWin* win, const char* const message, gboolean request_
         recipient_device_id = g_hash_table_lookup(omemo_ctx.device_list, recipients_iter->data);
         if (!recipient_device_id) {
             log_warning("[OMEMO][SEND] cannot find device ids for %s", recipients_iter->data);
-            win_println(win, THEME_ERROR, "!", "Can't find a OMEMO device id for %s.\n", recipients_iter->data);
+
+            if (win_warn_needed(win, "omemo_no_device", recipients_iter->data)) {
+                win_println(win, THEME_ERROR, "!", "Can't find a OMEMO device id for %s.", recipients_iter->data);
+                win_warn_sent(win, "omemo_no_device", recipients_iter->data);
+            }
             continue;
         }
 
diff --git a/src/ui/win_types.h b/src/ui/win_types.h
index 2f83eb607..dddab862b 100644
--- a/src/ui/win_types.h
+++ b/src/ui/win_types.h
@@ -133,6 +133,7 @@ typedef struct prof_win_t
     ProfLayout* layout;
     Autocomplete urls_ac;
     Autocomplete quotes_ac;
+    GHashTable* warned_jids;
 } ProfWin;
 
 typedef struct prof_console_win_t
diff --git a/src/ui/window.c b/src/ui/window.c
index 178a2c0b0..a2fc10ea2 100644
--- a/src/ui/window.c
+++ b/src/ui/window.c
@@ -557,6 +557,10 @@ win_free(ProfWin* window)
     }
     free(window->layout);
 
+    if (window->warned_jids) {
+        g_hash_table_destroy(window->warned_jids);
+    }
+
     switch (window->type) {
     case WIN_CHAT:
     {
@@ -609,6 +613,44 @@ win_free(ProfWin* window)
     free(window);
 }
 
+gboolean
+win_warn_needed(ProfWin* window, const char* const type, const char* const jid)
+{
+    if (!window || !type || !jid) {
+        return TRUE;
+    }
+
+    if (!window->warned_jids) {
+        return TRUE;
+    }
+
+    auto_gchar gchar* key = g_strdup_printf("%s:%s", type, jid);
+    return !g_hash_table_contains(window->warned_jids, key);
+}
+
+void
+win_warn_sent(ProfWin* window, const char* const type, const char* const jid)
+{
+    if (!window || !type || !jid) {
+        return;
+    }
+
+    if (!window->warned_jids) {
+        window->warned_jids = g_hash_table_new_full(g_str_hash, g_str_equal, g_free, NULL);
+    }
+
+    gchar* key = g_strdup_printf("%s:%s", type, jid);
+    g_hash_table_insert(window->warned_jids, key, GINT_TO_POINTER(1));
+}
+
+void
+win_clear_warned_jids(ProfWin* window)
+{
+    if (window && window->warned_jids) {
+        g_hash_table_remove_all(window->warned_jids);
+    }
+}
+
 void
 win_page_up(ProfWin* window, int scroll_size)
 {
diff --git a/src/ui/window.h b/src/ui/window.h
index 026392eee..08e3e8e3e 100644
--- a/src/ui/window.h
+++ b/src/ui/window.h
@@ -59,6 +59,10 @@ void win_update_entry_message(ProfWin* window, const char* const id, const char*
 
 gboolean win_has_active_subwin(ProfWin* window);
 
+gboolean win_warn_needed(ProfWin* window, const char* const type, const char* const jid);
+void win_warn_sent(ProfWin* window, const char* const type, const char* const jid);
+void win_clear_warned_jids(ProfWin* window);
+
 void win_page_up(ProfWin* window, int scroll_size);
 void win_page_down(ProfWin* window, int scroll_size);
 void win_sub_page_down(ProfWin* window);
diff --git a/tests/unittests/ui/stub_ui.c b/tests/unittests/ui/stub_ui.c
index 4beb62006..2d0a200af 100644
--- a/tests/unittests/ui/stub_ui.c
+++ b/tests/unittests/ui/stub_ui.c
@@ -1318,6 +1318,22 @@ win_refresh_with_subwin(ProfWin* window)
 {
 }
 
+gboolean
+win_warn_needed(ProfWin* window, const char* const type, const char* const jid)
+{
+    return TRUE;
+}
+
+void
+win_warn_sent(ProfWin* window, const char* const type, const char* const jid)
+{
+}
+
+void
+win_clear_warned_jids(ProfWin* window)
+{
+}
+
 void
 win_println(ProfWin* window, theme_item_t theme, const char* ch, const char* const message, ...)
 {