A 50% battery loss overnight while a MacBook Pro with an M1 Max is asleep is not normal.
Even with 93% battery health, a 16-inch MacBook Pro should typically lose only 1% to 5% over 8 to 12 hours in Sleep Mode.
A loss of 50% almost always indicates that the Mac is either not remaining asleep or that a background process is preventing deep sleep.
The fact that this only began during the past few weeks makes it reasonable to consider a change introduced by a recent macOS update, although the update itself is not necessarily the direct cause.
Though the latest version of macOS is 26.5.2. Learn how to update the software on your Mac and how to allow important background updates.
More commonly, an update changes the behaviour of a driver, an application, Spotlight indexing, iCloud synchronization, or power management.
Leaving a 950-page Pages document open should not cause this problem.
Pages is designed to remain suspended during sleep, and a text-only document, even one approaching 1,000 pages, uses very little power once the Mac is asleep.
The most likely causes, in roughly the order I would investigate them, are:
- The Mac is repeatedly waking from sleep because of a background task.
- A process is preventing the system from entering deep sleep.
- Network activity, iCloud syncing, or Power Nap-like functions are waking the computer.
- An external device or Bluetooth accessory is waking the Mac.
- A software bug introduced by a recent macOS update. Though there is nothing specifically mentioned by Apple regarding Tahoe 26.5.2
The first thing I would examine is the battery usage history.
Open System Settings > Battery and look at the battery graph.
If the graph shows periods labeled Screen On or Screen Idle during the night when the Mac should have been asleep, then the computer is waking repeatedly instead of remaining asleep.
Next, determine what actually happened while the Mac was asleep.
Open Terminal and enter:
pmset -g log | grep -i "Wake"
The command often reveal exactly what caused each wake event, such as:
- Bluetooth
- Power Management
- Network
- USB device
- lid open
- maintenance wake
- DarkWake
If you see dozens or hundreds of wake events overnight, that would explain the battery drain.
Another useful command is:
pmset -g assertions
If anything is preventing normal sleep, this command will often identify the responsible process.
Common examples include cloud synchronization services, media applications, backup software, or virtualization software.
If the problem began immediately after updating to macOS 26.5, Spotlight may also still be indexing. You can check this by using watching CPU activity in Activity Monitor.
I would also temporarily disable the following settings for one night as a test:
- Wake for network access
- Bluetooth devices allowed to wake the computer (disconnect any Bluetooth mouse or keyboard if practical)
- Any USB hubs or external drives
- Any SD cards or external accessories
Then put the Mac to sleep and compare the overnight battery loss.
One additional possibility is that the notebook is not actually entering sleep because a background process is holding a power assertion.
This has occasionally occurred after macOS updates, where a system process or third-party application inadvertently prevents deep sleep.
Download the Application Etrecheck ( External Link ) directly from the Developer.
This is a Diagnostic Tool that makes no changes to the computer.
It makes a coherent and readable inventory of both the Hardware and Software used on the computer
The application is free or paid for added features.
The Report will Not Reveal Any Personal Information.
Post back the Full Report - Share Report >> Copy , then paste >>>> using the Additional Text Icon <<<<
Based on your description, my leading suspicion is that the Mac is experiencing repeated DarkWake events or another process preventing deep sleep, rather than a failing battery.
A battery at 93% health would not suddenly begin losing half its charge overnight solely because of normal aging. The sleep logs and pmset output should identify the underlying cause.
