Protect shapes, layers, or entire diagrams from changes before sharing them with your team.

Lock or unlock shapes

  1. Select File > Options > Advanced, and select Run in developer mode.

  2. Select a shape, and select Developer > Protection.

  3. Select the check boxes for the shape attributes you want to lock.

    Or, clear the check boxes you want to unlock.

  4. Select OK.

Lock or unlock layers

When a layer is locked, shapes can’t be selected, moved, edited, or added. To lock or unlock a layer:

  1. Select Home > Layers > Layer Properties.

  2. Select the Lock check box to lock the layer.

    Or, clear the Lock check box to unlock it.

Prevent changes to the entire diagram

Create a PDF file to share with reviewers.

  1. Select File > Export.

  2. Select Create PDF/XPS.

  3. Select where to store the file.

  4. Select Publish.

Source: Microsoft