Severe Battery Drain and overheating on MacBook Pro M5 after upgrading to macOS 27 Golden Gate

I’m experiencing severe battery drain and overheating on my MacBook Pro since upgrading to macOS 27, and I’m wondering if anyone else is experiencing the same issue.

I purchased this MacBook Pro in May 2026, so the computer and battery are still relatively new. Before the macOS 27 upgrade, battery life was excellent and I had no overheating issues.

Since installing macOS 27, the behavior has changed dramatically.

For example, I can leave the MacBook unplugged overnight without actively using it, and by the next morning the battery can be completely drained. I have also noticed that the MacBook gets unusually warm or hot even when it is sitting idle.

Before the upgrade, I could leave it unplugged overnight and the battery percentage would barely change.

It has now been almost a full week since I upgraded to macOS 27, and the problem is still happening.

I know that after a major macOS update the system can run background processes such as Spotlight indexing, Photos analysis, iCloud synchronization, and other optimization tasks. I completely understand that this can temporarily increase CPU usage and battery consumption.

However, after almost a week, I find it very difficult to believe that this level of battery drain and heat can still be explained simply by "indexing."

Losing most or all of the battery overnight while the MacBook is essentially idle seems excessive, especially considering that this behavior started immediately after the macOS 27 upgrade.

Has anyone else experienced:

  • Significant battery drain while the MacBook is sleeping or idle?
  • The MacBook becoming warm or hot without actively using it?
  • Background processes continuing to consume significant power several days after upgrading?
  • Battery life becoming dramatically worse compared with the previous macOS version?

If anyone has identified a specific process or service responsible for the battery drain, I would really appreciate hearing what you found.

I would also be interested to know whether anyone has found a solution or if this appears to be a macOS 27 issue that Apple will need to address in an update.


MacBook Pro (M5 Pro, 2026)

Posted on Sep 22, 2026 8:42 AM

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Question marked as Top-ranking reply

Posted on Sep 22, 2026 8:47 AM

It is possible there are processes running in the background that are using significant resources. Check Activity Monitor, CPU tab (sort by % CPU) and Memory tab (sort by Memory) to see what's running hard.

 

Activity Monitor User Guide for Mac - Apple Support


Confirm that you have sufficient free space on your internal storage. Seems unlikely with a new Mac, but if you migrated from a prior Mac then you may be low on space. Another user reported rapid battery drain and it turned out there was only 8 GB free on that user's 512 GB storage.


The absolute minimum is ~20-25 GB free space, and as a rule of thumb you should aim to have 15-20% of your total internal storage as free space. Terminology is important here – free space is not the same thing as available space. The one that matters is Free space, but what macOS shows in most places is Available space. Available space includes both free space and ‘purgeable’ space, the latter comprises system caches, snapshots and other data that macOS can delete if it decides more free space is needed. However, there is no way the user can force those data to be purged.

 

The place to check how much Free space you have is in Disk Utility (in Applications > Utilities), by selecting the main container disk below the drive itself (you may need to select View menu > Show all devices to see it). For example, on my M4 MacBook Pro, the Storage settings pane and Get Info on the internal drive show 1.24 TB of Available space, whereas Disk Utility shows there is 1.15 TB of actual Free space, 90 GB less than ‘available’. Although 90 GB is a small fraction of my 2 TB internal storage, that would not be the case with 256 GB or 512 GB of internal storage.



Note that you can also see the Free space in the System Report (System Settings > General > About > System Report button, at the bottom > Storage). 

 

Some steps to take to safely free up space:

Free up storage space on Mac - Apple Support

Optimize storage space on your Mac - Apple Support

How to free up ‘System Data’ and other st… - Apple Community

 

 

If nothing in the above reveals an obvious culprit, then appropriate troubleshooting steps are Safe Mode and creating a new user account to test. 

 

See if the problem is present when you boot in safe mode. That process performs some system cleanup and clears caches, and also disables 3rd party extensions that may cause problems.

 

Start up your Mac in safe mode - Apple Support


If that does not correct the issue, test in a new user account. A newly-created user account will have all settings at default, and if the issue does not occur in that new account then it provides guidance on what may need to be changed to correct the issue.

 

Add a user or group on Mac - Apple Support

 

Once the testing is complete, the new account can easily be deleted.

 

Delete a user or group on Mac – Apple Support


If you have 3rd party ‘protection’ software installed, that may be the problem. That includes:

Cleaners (software claiming to automatically free up space)

Optimizers (software claiming to make your Mac run faster)

Antivirus software

VPN software (unless provided by a school/employer to enable access to internal resources from a remote location)

 

Such 3rd party system ‘helpers’, ‘cleaners’ and ‘protectors’ do more harm than good. In fact, such products are completely unnecessary for macOS and the only ‘good’ (if you want to call it that) they do is to put money in the developers’ pockets. Cleaners and protectors cause compatibility issues, often after macOS updates. Commercial VPNs claim to hide your browsing activity from websites, and while that may be true those VPN providers just sell your browsing data to others. For the user, all of these types of software offer only harm…and if that is limited to harm to your bank account, then count yourself lucky. If you have installed such software, follow the developer’s instructions to completely uninstall it (note that some developers fail to provide instructions and their software installs can be pervasive, meaning the only way to truly remove it is to erase your Mac, reinstall macOS then restore your user files from a backup).

 

It might help to download and run EtreCheck, written by a long-time forum member. The free version is fine. Post the full report using the Additional Text button. No personal information is revealed. 



Personally, I have been running macOS 27 Golden Gate on my 16" M4 Pro MBP since the upgrade came out, and have had no issues with battery life (which was a good thing, since I was at a conference for a couple of days running on battery for ~10 hours, and had 50% battery left at the end of each day).

19 replies

Sep 29, 2026 7:29 PM in response to mikee87

I am facing the exact same issue on my M5 Air, right after installing MacOS27. I can attribute it to applications I use the most, but that's not how you fix these issues. There is no additional app I have started using upon installing the new OS and my battery drains in 4-5 hours of use. Earlier (just until last week) it easily used to last for more than 10-12 hours. Apple should fix these issues before releasing such uncooked operating systems. What have they been doing with months of beta testings? It's atrocious!

Oct 17, 2026 2:22 PM in response to candersen114

Thanks for the suggestion. I looked into the dasd issue, but I have no indication that this is happening on my Mac. My logs show recurring DarkWake events every 15–18 minutes, including wifibt SMC.OutboxNotEmpty, even with Wi-Fi and Bluetooth disabled. I haven’t observed the high CPU usage described in the article. So far, the evidence points more towards a sleep/wake issue in macOS 27, although I can’t confirm the exact cause yet.

Severe Battery Drain and overheating on MacBook Pro M5 after upgrading to macOS 27 Golden Gate

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