Unplugged Mac won't back up to Time Machine when option is set to "back up on battery power"

Question

Level 1

8 points

Unplugged Mac won't back up to Time Machine when option is set to "back up on battery power"

Both of our unplugged Macs (2018 MacBook Pro 15-inch & 2022 MacBook Air M2) will not back up to Time Machine overnight when option is set to "back up on battery power". Battery is 100% at night and 95% first thing in the morning, so it drains 5% overnight just idling. Once plugged in when we wake up in the morning, automatic Time Machine backups resume. Why won't the "back up on battery power" setting work properly?

We both have our Macs plugged in all day long because we operate them in clamshell mode with an external monitor. Unfortunately, they must be plugged in during all waking hours because of the the external monitor. We unplug them at night because constant power 24/7/365 is bad for the battery. Both of our old Macs' batteries swelled over time and had to be replaced because they were always plugged in.

Posted on Aug 30, 2023 10:07 AM

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Answer 1

hc1111

Community Specialist

Aug 31, 2023 10:13 AM in response to Metal CPA

Hey there Metal CPA,

For help with backing up via Time Machine, try working through the guidance here first:

Make sure that you set up Time Machine correctly and are using a backup disk supported by Time Machine.

Make sure that your backup disk is connected directly to your Mac, unless you're using a network backup disk. Don't connect it through a USB hub or other device.

Use Disk Utility to repair your backup disk.

If you're using a network backup disk:

* Make sure that the network connection is good and your Mac is connected to the same network as the backup disk.

* Check for VPN software or other third-party security software that could be affecting the connection to your backup disk.

* If you completed a previous network backup successfully, verify that backup: Press and hold the Option key while choosing Verify Backups from the Time Machine menu in the menu bar.

Make sure that the firmware of your backup disk is up to date. Check with the manufacturer of the backup disk for details.

If no other solutions work, start over: Erase your backup disk, then use Time Machine to select it as your backup disk again.

If you can't back up or restore your Mac using Time Machine - Apple Support

Take care!

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Answer 2

Metal CPA Author

Level 1

8 points

Aug 31, 2023 2:24 PM in response to hc1111

HC1111, your steps seem pretty drastic when I know the backups are working properly. The only issue is when I unplug the Mac.

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Answer 3

JJRASC

Community Specialist

Aug 31, 2023 2:28 PM in response to Metal CPA

Hi, Metal CPA.

It may be best to contact Apple Support directly for more help with your Mac: Apple Support.

Cheers!

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Answer 4

ku4hx

Level 7

21,359 points

Sep 1, 2023 5:10 AM in response to Metal CPA

Wiping your drive and reinstalling the OS can be a drastic move, but the steps listed by hc1111 are just standard troubleshooting approaches.

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Answer 5

Metal CPA Author

Level 1

8 points

Sep 1, 2023 8:38 AM in response to Metal CPA

As it turns out, I called AppleCare yesterday. They said that even though Time Machine has a setting "back up on battery power", it's not supposed to do automatic backups on battery power. You can always force a manual backup on battery power.

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