An older MSI laptop previously had its boot mSATA SSD replaced and worked normally for about a year. The owner later removed that drive because he thought it was making noise or causing problems. The laptop still contains another mSATA SSD and a 2.5-inch SSD, but I can't get it to boot into the Windows installer from a USB drive. The BIOS detects the USB, and I've tried selecting it as the first boot device and choosing it from the F11 boot menu. Instead, it either returns to the BIOS or enters a boot loop showing error 0xc000021a.
The USB installer worked recently on another computer, so it seems unlikely to be the cause. I've also disabled Secure Boot and changed a few other boot settings without success. Interestingly, if I remove the USB drive, the laptop can still boot normally. The laptop is roughly 10–11 years old and uses a fourth-generation Intel processor. What should I try next?
3 Answers
Try switching between UEFI and Legacy/CSM mode. Some older laptops have unusual or limited UEFI firmware, even when the processor itself is 64-bit. If the installer was created for UEFI but the laptop is set to Legacy, or vice versa, it may never load correctly. Recreating the installer in the matching mode is worth trying too.
Disconnect all internal drives temporarily and try booting only from the USB installer. If that works, reconnect the SSDs one at a time. One of them may be failing or may contain an old bootloader that is interfering with startup. This also helps separate a USB-boot problem from a damaged internal drive.
Start by loading the BIOS defaults, then check whether a BIOS update is available for the exact MSI model. With a laptop this old, mismatched UEFI and Legacy/CSM settings can also prevent the installer from starting. The USB and the BIOS need to use compatible boot modes—typically UEFI with a GPT installer, or Legacy/CSM with an MBR installer.
I’m not sure of the exact CPU, but the laptop appears to be around 10 or 11 years old. I’ll reset the BIOS settings and check for an update first.