diff --git src/wp-includes/js/media-views.js src/wp-includes/js/media-views.js
index 5b10a05d5f..bfece3dbd0 100644
--- src/wp-includes/js/media-views.js
+++ src/wp-includes/js/media-views.js
@@ -3878,7 +3878,7 @@ Post = Select.extend(/** @lends wp.media.view.MediaFrame.Post.prototype */{
 					style:    'primary',
 					text:     editing ? l10n.updateGallery : l10n.insertGallery,
 					priority: 80,
-					requires: { library: true },
+					requires: { library: true, uploadingComplete: true },
 
 					/**
 					 * @fires wp.media.controller.State#update
@@ -5288,7 +5288,8 @@ Toolbar = View.extend(/** @lends wp.media.view.Toolbar.prototype */{
 			}
 
 			var requires = button.options.requires,
-				disabled = false;
+				disabled = false,
+				modelsUploading = ! _.isEmpty( library.findWhere(  { 'uploading': true } ) );
 
 			// Prevent insertion of attachments if any of them are still uploading
 			if ( selection && selection.models ) {
@@ -5297,6 +5298,10 @@ Toolbar = View.extend(/** @lends wp.media.view.Toolbar.prototype */{
 				});
 			}
 
+			if ( requires.uploadingComplete && modelsUploading ) {
+				disabled = true;
+			}
+
 			if ( requires.selection && selection && ! selection.length ) {
 				disabled = true;
 			} else if ( requires.library && library && ! library.length ) {
diff --git src/wp-includes/js/media/views/frame/post.js src/wp-includes/js/media/views/frame/post.js
index 8c8906e26b..646431502a 100644
--- src/wp-includes/js/media/views/frame/post.js
+++ src/wp-includes/js/media/views/frame/post.js
@@ -574,7 +574,7 @@ Post = Select.extend(/** @lends wp.media.view.MediaFrame.Post.prototype */{
 					style:    'primary',
 					text:     editing ? l10n.updateGallery : l10n.insertGallery,
 					priority: 80,
-					requires: { library: true },
+					requires: { library: true, uploadingComplete: true },
 
 					/**
 					 * @fires wp.media.controller.State#update
diff --git src/wp-includes/js/media/views/toolbar.js src/wp-includes/js/media/views/toolbar.js
index 258d12697a..eb825af8e5 100644
--- src/wp-includes/js/media/views/toolbar.js
+++ src/wp-includes/js/media/views/toolbar.js
@@ -140,7 +140,8 @@ Toolbar = View.extend(/** @lends wp.media.view.Toolbar.prototype */{
 			}
 
 			var requires = button.options.requires,
-				disabled = false;
+				disabled = false,
+				modelsUploading = ! _.isEmpty( library.findWhere(  { 'uploading': true } ) );
 
 			// Prevent insertion of attachments if any of them are still uploading
 			if ( selection && selection.models ) {
@@ -149,6 +150,10 @@ Toolbar = View.extend(/** @lends wp.media.view.Toolbar.prototype */{
 				});
 			}
 
+			if ( requires.uploadingComplete && modelsUploading ) {
+				disabled = true;
+			}
+
 			if ( requires.selection && selection && ! selection.length ) {
 				disabled = true;
 			} else if ( requires.library && library && ! library.length ) {