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This may be a signal that the Harmony remote needs to have its firmware updated, which is done in Harmony Safe Mode.
As for entering - and exiting - Safe Mode on a Harmony, to enter you hold down the OFF button, while putting in the batteries.
To EXIT from Safe Mode, on the other hand, you
1: remove the batteries.
2: hold down the Z button.
3: while holding that button down, replace the batteries... and the remote will start up into normal mode and function, and you can use it again.
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