Symptoms
- Every boot requires manually navigating out of BIOS setup
- Sometimes exiting BIOS lets Windows load fine afterward
- Clock/date may reset between sessions
- Started after a power outage or battery change
Likely causes
- CommonDead or weak CMOS batteryThis is the classic cause when settings don't stick between power-offs.
- CommonA BIOS setting is set to always enter setupSome systems have an explicit setting for this that can get toggled accidentally.
- PossibleBoot drive intermittently not detected in timeA marginal cable connection can cause the BIOS to fail to find a boot target on some power-ons.
- PossibleCorrupted BIOS settings after a failed updateFirmware updates that don't complete cleanly can leave inconsistent settings.
- Less commonKeyboard stuck sending the 'enter setup' keyA physically stuck key (like Delete or F2) can trigger this every time.
What to do
- Check whether the system clock/date resets each time you enter BIOS; if so, the CMOS battery is likely dead and should be replaced.
- While in BIOS, load 'optimized defaults' or 'setup defaults,' save, and exit to rule out a stray setting causing this.
- Check the boot order list to confirm your Windows drive is listed and set first, then save and exit.
- For desktops, verify no key is physically stuck by removing the keyboard entirely and testing a boot without one attached.
- If it's a laptop, check for a stuck key by very gently pressing and releasing keys near Delete, Esc, and the function row.
- If the CMOS battery is suspected, it's typically a small coin-cell battery on the motherboard (desktops) that's inexpensive and straightforward to replace, though on laptops it usually requires opening the case.
- If defaults and battery replacement don't help, the motherboard's firmware chip itself may be failing and needs professional evaluation.
Tools and parts
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When to call a pro
If replacing the CMOS battery and resetting BIOS defaults doesn't stop it from entering setup every time, a technician should check the motherboard for a deeper firmware fault.
Safety
Generally low risk
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.