If you're "Read More" buttons have "disappeared" this is not actually anything that is broken.
Blogger/Google reset the "Read More" text so that it is no longer automatic. If you are using Read More buttons, you must input your own custom text or no text will appear in the buttons.
This affects new blogs and some old blogs if you didn't add your own custom text to start with.
To add text to the Read More buttons:
- On the Blogger Dashboard, go to the Layout page.
- Find the Blog Posts gadget box and click on the Edit link.
- The Configure Blog Posts settings box will open.
- In the Post page link text field, you will need to enter the text that will appear on your Read More button.
- Click the orange Save button when done.
THAT'S IT, ALL "FIXED"!