All Files Locking and Unlocking Layers You can lock a selected layer to protect any objects on it from being changed. Once locked, you can unlock the layer to make changes to any objects on it. How to lock or unlock a layer Do one of the following: In the Layer panel or the Layers view, click the Lock/Unlock icon just left of the layer. In the Thumbnails view, click on the Lock/Unlock icon just beneath the layer's name. In the Layer panel, the Layers view or the Thumbnails view, select the layer. Then, do one of the following:Then, select Layer > Lock/Unlock Layers from the top menu.In the Layer toolbar, click on the Lock/Unlock Layers button.Press Alt + L.