macOS 26 and 26.0.1 has my battery on my MacBook Pro M2 Max draining way too fast

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

Activity Monitor User Guide for Mac - Apple Support

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In addition to some change in Tahoe, it is very likely that some older software running in the background is not fully compatible and may be draining more resources.

You may also keep Activity Monitor running for a while and keep an eye on the Energy tab.

This may give you an indication of which processes in your Mac are using the most power.

FWIW, I see no more nor less battery usage with Tahoe vs Sequoia. Maybe this differs with the age and model of macs, though.

In addition to my previous post: in the Energy tab you can see not only which apps are using more energy now, but also in the past 12 hours, which may be useful. In my typical usage, Safari tends to come first on accumulated energy use, because it is open all the time, with many tabs, and often playing something in the background. Mail is a distant second (also running permanently and checking for new mail every 5 minutes). See if you have some unexpected entry near the top of the list.

wesleyfranks wrote:

[...] If it doesn't get fixed in the next few versions I may need to backup my files and restore the system to an older OS version.

You'd best be backing up your files now and continuously, before you need the backup. Once things actually go south you'll be happy that you didn't wait. Bad things happen at the worst times.

neuroanatomist wrote:

It is possible there are processes running in the background that are using significant resources.

I have the same issue, and my usage of the MacBook didn't change since before the update. Hence, background processes are the same as before, unless MacOS added new ones, hence the problem is on the OS. I already had to disable Apple Intelligence as my battery where lasting just 1h30 being connected to a projector. Still this morning I had a 1h call and Safari (from where I opened the website for the call) drained more than 50% of my battery. 2 weeks ago this wasn't happening.

apgl wrote:

neuroanatomist wrote:

It is possible there are processes running in the background that are using significant resources.

I have the same issue, and my usage of the MacBook didn't change since before the update. Hence, background processes are the same as before, unless MacOS added new ones, hence the problem is on the OS.

Impressive that you know the background processes are the same, and that every single piece of software and every extension you have on your system that was running under Sequoia is perfectly compatible with Tahoe. With that level of certainty, I guess there’s no point in investigating further. Just wait for Apple to fix it. No doubt they will.

For me the problem looks to be Spotlight. Code has integrated codex, so it's normal, it doesn't worry me. However, I don't really find the energy tab trustable, 283 may mean anything, without an actual % impact I can't understand what consumed 50% of my battery during my call.

[Edited by Moderator]

Sorry if I looked too much aggressive in my previous message, wasn't my intention. I didn't even want to look "certain" of my assumptions. I continuously check the Activity Monitor and I didn't notice anything extra-ordinary in the last week except CPU usage peaks from Spotlight and Safari.