Sony Reader "Exceptional internal memory state: formatting" workaround

I get a strange error from time-to-time on my Sony Reader (PRS-650).

After the Reader powers up, it does the busy spinner and then says:

+---------------------------------------+
| Exceptional internal memory state     |
| Formatting                            |
|                              [  OK  ] |
+---------------------------------------+

At this point pressing OK will format the device. Yikes!

Workaround

  1. Do not press OK on the format warning
  2. Instead, plug device into your computer
  3. Backup READER partition (optional, but recommended)
  4. Press hardware RESET button with paperclip
  5. Wait for Reader to reboot (no PRS+ features when booting with USB connected)
  6. Unplug from computer
  7. Shutdown/restart reader (PRS+ features will be re-enabled)
  8. Problem is gone!

Cause

My theory is that PRS+ doesn’t the device being “dirty” when it is unmounted or ejected improperly.

--
Comments: @gingerbeardman