"Most recent backup did not complete because your computer was running on battery"?

look in this article to get started.

Time Machine troubleshooting on Mac - Apple Support

it links to this article which describes how to get Time machine to fix up the backup drive:

Verify your backup disk on Mac - Apple Support

if it will not proceed after the verify, post back for more complex options to get it to "go".

.

if telling it to back Up now does not work, your backup drive may have been ejected, or the backup drive may be corrupted.

First, be certain you can see the connected drive in Finder, and check to see that there are some accessible files on it. ANY is all we are looking for at this stage.

Next, use the steps in this old but still applicable article by the last James Pond:

Time Machine - Troubleshooting C19. Backup delayed or The backup disk is not available

That computer is a battery-CAPABLE device. It is not optimized as a battery-operated device. (It is NOT an iPhone.)

Your computer performs best when connected to AC power. It can use the full output of the Power Adapter AND when doing especially challenging work will also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may decline during stressful work.

When used only on battery, your computer has no extra cushion of power, and may perform more slowly. However, for ordinary non-stressful tasks this may not be objectionable (possibly not even noticeable.)

In general, you should ALWAYS connect AC power when it is possible to do so, and only run on batteries (which could be somewhat slower) when no AC sources are at hand. Your Mac will NEVER over-charge.

"Most recent backup did not complete because your computer was running on battery"?

"Exactly WHERE are you seeing this?

in Notifications?

in the overall status shown in Time machine control panel?"

In the top bar when I click on the Time machine icon.

You can open Time machine preferences ANYTIME -- just take a look at the status of your last backup.

if you last backup completed fine, then the old message is not going away, and you found a BUG!

if the status of your last backup still says did not complete, thats a real problem, and needs to be fixed.

select back up NOW.

It should look at the old backups, complete and incomplete, and decide the best way forward.

if that message now ONLY appears in Notification Center, move your mouse around the notification and a dismiss (x) may appear in the upper left Corner of the notification. or choose '(Show More)' and 'Mark as Read'.

if it does not come back, you fixed it.

Exactly WHERE are you seeing tis?

in Notifications?

in the overall status shown in Time machine control panel?

is that the SAME status shown iwhen you open time machine preferences?

....

if you use posts from random people on the Internet as your guide, anything you can think of can be found to be "a common problem'. and also, its opposite. Readerswhere mostly ignore what is or what ain't a "common problem".

Please pay no attention whatsoever to what others are experiencing. Tell us more about your SPECIFIC complaint, instead.

Ddoes the problem clear up after a while, or did the stalled backup cause your backups to NEVER complete after that one? are they working now? what is the date shown for last backup?

<<. my latest backup was on November 7th. >>

Today is November 21. Why in the world are you waiting so long to allow time machine to run? its default setting is Hourly incremental backups.

Time machine works quietly and automatically in the background, without interrupting your regular work. Time Machine's "claim to fame" is that it is the backup that gets done, because it does not ruin performance of the rest of the computer while doing its backup operations. You do not have to set aside a "Special Time" when you only do backups. When you need it, your Time machine Backup is much more likely to be there.

I have two destinations for my backups. Time machine automatically alternates between the two independent backup sets.

One is a drive, locally attached to my computer. Yes, I keep it connected all the time, but I do not ask everyone to do that. But consider connecting it once a day.

The other is a shared backup destination connected to my basement MacOS server. It is always connected across my home network. Because it is not local to my computer, two things change. Its backups are maintained inside a sparse bundle disk image, a 'Volume inside a file'.

That Shared Backup Destination is what can be checked with 'Verify Backups'. I was mistaken when I suggested it for LOCAL backup disks. It appears Apple expects you to check locally-attached backups by just running Disk Utility Repair/FirstAid on the local backup disk.

I have the exact same problem. I get the message "the most recent backup didn't complete because your computer was running on battery" every time it reminds me to backup, even though my brand new Macbook Air was absolutely plugged in and I have not selected the option to "backup on battery". If I look in the dropdown Time Machine menu it tells me when my last backup was and doesn't say anything is wrong. When I do the procedure above to verify my backup disc, I hold the option key and see verify backups but it is greyed out and I cannot select it. And yes, this is with my backup disc plugged into my computer and visible on my desktop.

Hi Grant, I guess I have been unclear. It appears to back-up perfectly but then I get that not completed, running on battery message later on. Right now it says that my latest backup was on November 7th, but I still get that message. Maybe just ignore it? I would like to be able to do the "verify backups" which is always grayed out.