I was working in a spreadsheet for several hours saving my work periodically.  Within two of those hours I suddenly lost the ability to add a new note or a new comment.  I right clicked on the cell that I wanted to add the note. Surprised to see the options were missing.  I found instructions for a work around that I pasted below.  However, I cannot get past Step 4 (Press F5 to run the code)  It presented an error.  I clicked 'debug' and an arrow showed me the line with the error but no suggestion as to how to correct.  I still can't add notes or comments to my Excel spreadsheet.

Missing New Comment and New Note from Excel's context menu

Last Updated: August 30, 2019

ISSUE

If you have customized Excel's right-click context menu (possibly using an add-in), you may discover that the New Comment, and New Note options are missing after you update Office.

STATUS: WORKAROUND

To fix this, reset your customized context menus using VBA (Visual Basic for Applications). 

Follow these steps to implement the workaround:

1. Open the Visual Basic Editor (VBE) by pressing Alt+F11.

2. Insert a new module from Insert > Module.

3. Copy and paste the following code into the empty module pane on the right:

   Sub ShowButtonsAgain()
      Dim bar As CommandBar
      For Each bar In Application.CommandBars
            bar.Reset
      Next
   End Sub

4. Press F5 to run the code.

5. Exit back to Excel by pressing Alt+Q, and verify that the Comment and Note options have been restored.

If the issue recurs, then you can create a reusable procedure:

1. Follow steps 1-5 above.

2. Save the workbook in a convenient location where you can quickly access it if needed. Alternately, you can save it in Excel's https://support.office.com/en-us/article/copy-your-macros-to-a-personal-macro-workbook-aa439b90-f836-4381-97f0-6e4c3f5ee566 if you always want to have the procedure available.