I’m having an issue with my APC UPS and I’m trying to understand what the continuous beeping means.

Setup / context

• I have an APC UPS
• New battery installed about 1 week ago
• No devices are plugged in when testing
• PC setup normally connected, but currently testing with no load

What happens

1. There was a power outage last night
2. The UPS switched to battery mode and started beeping (normal)
3. I then long-pressed the power button (~5 seconds) to shut it off while it was on battery
4. In the morning, I turn it on again (long press power button 5 seconds as usual)
5. It powers on, but immediately starts a continuous, non-stop beep that does not stop

What I already tried

• Unplugged all devices (no load connected)
• Turned it off and on again
• Confirmed battery is new and installed properly
• The UPS does not show any obvious overload situation

Important observation

This only happens after I force-shut it down during a blackout (battery mode). If I don’t force shut it down, it behaves normally. I usually leave it on all the time, but these annoying blackouts force me to turn it off, which then poses this problem the next morning.

Question

What does a continuous solid beep on startup usually mean for APC UPS units? Is this a fault state, battery calibration issue, or something else?