When installing manually, _it is critical that the firmware file downloaded is unzipped or decompressed _prior to transfer to the Sansa. Additionally, the file must be placed in the root directory, and not in any of the folders present.
When you unplug, the “firmware upgrade in progress” screen will appear.
There is a normal delay of a few days between posting the latest firmware builds here on the forum, and inclusion to the automated Sansa Updater. If you have any problem installing manually, the Sansa Updater will transfer and decompress the file automatically for you, a few days after the initial release.