diff --git a/app/views/queries/_form.html.erb b/app/views/queries/_form.html.erb
index b70ef53df..8b52383de 100644
--- a/app/views/queries/_form.html.erb
+++ b/app/views/queries/_form.html.erb
@@ -32,7 +32,7 @@
 
 <% unless @query.is_a?(ProjectQuery) %>
   <p><label for="query_is_for_all"><%=l(:field_is_for_all)%></label>
-  <%= check_box_tag 'query_is_for_all', 1, @query.project.nil?, :class => (User.current.admin? ? '' : 'disable-unless-private') %></p>
+  <%= check_box_tag 'query_is_for_all', 1, @query.project.nil?, :disabled => (!@query.new_record? && @query.project.nil?), :class => (User.current.admin? ? '' : 'disable-unless-private') %></p>
 <% end %>
 
 <% unless params[:calendar] %>
diff --git a/test/functional/queries_controller_test.rb b/test/functional/queries_controller_test.rb
index 7f446f2b4..4f0827da8 100644
--- a/test/functional/queries_controller_test.rb
+++ b/test/functional/queries_controller_test.rb
@@ -1030,4 +1030,44 @@ class QueriesControllerTest < Redmine::ControllerTest
     assert_include ["Development", "10"], json
     assert_include ["Inactive Activity", "14"], json
   end
+
+  def test_new_query_is_for_all_checkbox_not_disabled
+    @request.session[:user_id] = 1
+    get :new
+    assert_response :success
+    # Verify that the "For all projects" checkbox is not disabled when creating a new query
+    assert_select 'input[name=query_is_for_all][type=checkbox][checked]:not([disabled])'
+  end
+
+  def test_new_project_query_is_for_all_checkbox_not_disabled
+    @request.session[:user_id] = 1
+    get(:new, :params => {:project_id => 1})
+    assert_response :success
+    # Verify that the checkbox is not disabled when creating a new query within a project
+    assert_select 'input[name=query_is_for_all][type=checkbox]:not([checked]):not([disabled])'
+  end
+
+  def test_edit_global_query_is_for_all_checkbox_disabled
+    @request.session[:user_id] = 1
+    # Create a global query (project_id = nil)
+    query = IssueQuery.create!(:name => 'test_global_query', :user_id => 1, :project_id => nil)
+
+    get(:edit, :params => {:id => query.id})
+    assert_response :success
+
+    # Verify that the "For all projects" checkbox is disabled when editing an existing global query
+    assert_select 'input[name=query_is_for_all][type=checkbox][checked][disabled]'
+  end
+
+  def test_edit_project_query_is_for_all_checkbox_not_disabled
+    @request.session[:user_id] = 1
+    # Create a project-specific query
+    query = IssueQuery.create!(:name => 'test_project_query', :user_id => 1, :project_id => 1)
+
+    get(:edit, :params => {:id => query.id})
+    assert_response :success
+
+    # Verify that the checkbox is not disabled when editing a project-specific query
+    assert_select 'input[name=query_is_for_all][type=checkbox]:not([checked]):not([disabled])'
+  end
 end