diff --git a/rtdata/languages/English (UK) b/rtdata/languages/English (UK)
index 37ccdc48f..5d22fa61f 100644
--- a/rtdata/languages/English (UK)	
+++ b/rtdata/languages/English (UK)	
@@ -2154,7 +2154,7 @@ TP_WBALANCE_PATCHLABEL_TOOLTIP;Display number of read colours (max=237).\nDispla
 !PREFERENCES_PARSEDEXT;Parsed Extensions
 !PREFERENCES_PARSEDEXTADD;Add extension
 !PREFERENCES_PARSEDEXTADDHINT;Add entered extension to the list.
-!PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.
+!PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.\nPredefined extensions cannot be deleted.
 !PREFERENCES_PARSEDEXTDOWNHINT;Move selected extension down in the list.
 !PREFERENCES_PARSEDEXTUPHINT;Move selected extension up in the list.
 !PREFERENCES_PERFORMANCE_MEASURE;Measure
diff --git a/rtdata/languages/English (US) b/rtdata/languages/English (US)
index 079713ac1..4cd01622a 100644
--- a/rtdata/languages/English (US)	
+++ b/rtdata/languages/English (US)	
@@ -1971,7 +1971,7 @@
 !PREFERENCES_PARSEDEXT;Parsed Extensions
 !PREFERENCES_PARSEDEXTADD;Add extension
 !PREFERENCES_PARSEDEXTADDHINT;Add entered extension to the list.
-!PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.
+!PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.\nPredefined extensions cannot be deleted.
 !PREFERENCES_PARSEDEXTDOWNHINT;Move selected extension down in the list.
 !PREFERENCES_PARSEDEXTUPHINT;Move selected extension up in the list.
 !PREFERENCES_PERFORMANCE_MEASURE;Measure
diff --git a/rtdata/languages/default b/rtdata/languages/default
index 75d060dec..7a4c8aea7 100644
--- a/rtdata/languages/default
+++ b/rtdata/languages/default
@@ -2038,7 +2038,7 @@ PREFERENCES_PANFACTORLABEL;Pan rate amplification
 PREFERENCES_PARSEDEXT;Parsed Extensions
 PREFERENCES_PARSEDEXTADD;Add extension
 PREFERENCES_PARSEDEXTADDHINT;Add entered extension to the list.
-PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.
+PREFERENCES_PARSEDEXTDELHINT;Delete selected extension from the list.\nPredefined extensions cannot be deleted.
 PREFERENCES_PARSEDEXTDOWNHINT;Move selected extension down in the list.
 PREFERENCES_PARSEDEXTUPHINT;Move selected extension up in the list.
 PREFERENCES_PERFORMANCE_MEASURE;Measure