What a easy fix! I'm using Excel 2000 (I know, a dinosaur) and have tons of comments (1500+). Just started to work on my file this morning and realized that I could edit some comments but others I couldn't.
If this has happened to you...
You can see comments, but when you click "Edit comments" you can't see the comment box.
How to fix! Say your comment is in column C, goto the top cell with a comment in that column. Drag that column out to make it wider, then click "Edit Comment." You should see that its "underneath" that cell. Drag the comment box out to the right. Fix your column width. This also fixed ALL the rest of my uneditable comments.
If this has happened to you...
You can see comments, but when you click "Edit comments" you can't see the comment box.
How to fix! Say your comment is in column C, goto the top cell with a comment in that column. Drag that column out to make it wider, then click "Edit Comment." You should see that its "underneath" that cell. Drag the comment box out to the right. Fix your column width. This also fixed ALL the rest of my uneditable comments.