STATUS_WAKE_SYSTEM 0X40000294 — PC Keeps Waking Up From Sleep

First Thing: Check What Woke It Up (90% of the Time It's a Timer)

Before you go down any rabbit holes, run this command in Command Prompt (Admin):

powercfg /lastwake

That spits out exactly what yanked your PC out of sleep. 9 times out of 10, you'll see something like Wake Timer or a specific device name. Had a client last month whose PC woke every night at 3 AM — turned out to be a Windows Update scheduled task set to "wake the computer to install updates." Drove 'em nuts for weeks.

If you see a timer listed, don't panic — that's the cause, not a glitch. Now kill it.

Cause #1: Wake Timers from Scheduled Tasks

Windows schedules stuff like updates, maintenance, or third-party apps (looking at you, Adobe updaters) that have permission to wake your PC. The fix is simple: disable wake timers globally or per-task.

Disable All Wake Timers (Quick Way)

1. Open Control Panel > Power Options.
2. Click Change plan settings next to your active plan.
3. Click Change advanced power settings.
4. Expand Sleep > Allow wake timers.
5. Set both On battery and Plugged in to Disabled.

This stops every scheduled task from waking the PC. If you still need Windows Update to wake for downloads, skip this and do the per-task method instead.

Per-Task Control (More Granular)

Open Task Scheduler, go to Task Scheduler Library, find the offending task (check History tab for wake events), and uncheck Wake the computer to run this task in the Conditions tab. Common culprits: Windows Update, Adobe Flash Player Updater, Google Update, and Microsoft Edge Update.

Had a small biz client whose server kept waking for a nightly backup task that was set wrong. Unchecking that box fixed it instantly — no more 2 AM wake-ups.

Cause #2: Devices That Wake the PC (Mouse, Keyboard, Network Card)

Sometimes it's not a timer — it's a mouse jiggle, keyboard bump, or network activity. Most mice have touchy sensors that wake the PC if you breathe on the desk.

Stop Your Mouse and Keyboard from Waking the PC

1. Open Device Manager.
2. Expand Mice and other pointing devices.
3. Right-click your mouse, go to Power Management tab, and uncheck Allow this device to wake the computer.
4. Do the same under Keyboards.

Don't worry — your mouse will still work when you move it... once the PC is awake. This just stops it from waking the system while asleep.

Network Card Wake-on-LAN (The Sneaky One)

If your PC wakes after network activity (like a router broadcast or someone pinging it), your Ethernet adapter's Wake-on-LAN is the culprit.

1. In Device Manager, expand Network adapters.
2. Right-click your Ethernet controller (likely Realtek or Intel), go to Power Management.
3. Uncheck Allow this device to wake the computer.
4. Also check the Advanced tab — set Wake on Magic Packet and Wake on Pattern Match to Disabled.

I've seen Wi-Fi cards do this too, but wired is more common. If you're on Wi-Fi, check that adapter as well.

Cause #3: BIOS/UEFI Wake Settings (Less Common, but Nasty)

If both software fixes fail, the motherboard firmware might have its own wake schedule. Enter your BIOS setup (usually F2 or Delete during boot) and look for Wake on LAN, RTC Alarm, or Power On by Alarm. Disable anything that says "wake" or "alarm." Save and exit.

Had a client whose Dell OptiPlex had a BIOS setting that scheduled wake at 6 AM every day — no Windows setting could override it. Took 30 seconds in BIOS to kill it.

Quick-Reference Summary Table

That's it. 90% of the time it's a stupid wake timer from Windows Update or a mouse that thinks your cat brushing against the desk is a wake signal. Run powercfg /lastwake first, then kill the culprit. You'll be sleeping through the night in no time.