Battery draining rapidly on MacBook Pro M1 Pro after macOS 26 update

Slimmy111 wrote:

I have a Macbook pro on M1 PRO. After upgrading to macOS 26, the battery started to drain faster.After 2 hours of operation, when calling Slack, the battery drained from 100% to 33%

[Re-Titled by Moderator]

Original Title: The battery started to drain faster

There are many reports along these line with the upgrade.

—Shutting down and restarting more than once >Shut Down

—reinstalling the macOS on top of the existing macOS to sort upgrade anomalies has been known to resolve issues

Recovery (both M1/M2/M3/M4 and Intel) — How to reinstall macOS - Apple Support

no resolve—

To be proactive you can file a bug report / submit your Apple Feedback here: Product Feedback - Apple

unplug all non-essential peripherals when testing

Uninstall all third party apps that are Cleaners/Optimizers/VPN/Anti-Virus

all known to cause issues on the macOS

When you first install MacOS 26, it has DAYS of work to do. MacOS 26 wants to index and organize everything to give you very fast access to exactly what you might need to manipulate.

For example, the spotlight index (of every word in every file) must be re-built for lightning-fast searches. Your pictures are scanned for objects and faces to allow those to be manipulated as objects, rather than bitmaps.

Doing that that takes some investment of local compute power now. It is important to note, this uses LOCAL compute power -- your files are never uploaded anywhere else for analysis, in order to maintain your complete privacy.

After a few days, you will get remarkably better responsiveness in many different ways.

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, such as the power adapter. It can use the full output of the Power Adapter AND when doing especially challenging work could also freely "borrow" power from the battery. In some cases, even with the power adapter connected, the charged state may decline during very 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 a power source when it is possible to do so, and only run on batteries (which could be somewhat slower) when no power sources are at hand. Modern Macs maintain optimum battery charge levels under program control, and will NEVER over-charge. 

When you set it down to use in one place, or set it down for the night, plug it in. Then you won't CARE whether it would drain the battery.