No expert so I am just posting to start this off.
When I Googled, Connected USB. The timer and alarm will become invalid, I found a number of hits, but no specific cures. Perhaps you will have better luck.
If this is a new device and still under warranty, then you may want to consider seeking a return/replacement.
Mark
I have a sony nwz-s545 mp3 player. It worked perfectly until last week. Now I connect it to the computer, it says "Connected USB. The timer and alarm will become invalid", stays like this for 10-20 seconds, but then turns off, and will not charge. Resetting the unit does not make a difference. Could this be a problem with the battery ? How can I check or replace it ?

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