---
title: "Fixing an invalid boot disk error on an old laptop"
language: en
topics: ["MacBook", "SSH", "ThinkPad", "Windows", "cloud", "experiment", "hacking", "laptop", "linux", "networking", "programming", "repair", "retro", "vim", "webdesign"]
full_article_url: https://willem.com/en/2016-06-23_building-the-blog-in-style/
---
# Fixing an invalid boot disk error on an old laptop

*An empty BIOS battery resets the harddisk interface mode.*

> On my old Toshiba the cause was an empty BIOS battery: after years without power, the BIOS settings had reset, including the harddisk interface mode. Setting that mode back to enhanced IDE made the 2.1GB disk boot again.

My 1995 Toshiba T2130CT refused to start after years in a closet, showing only an invalid boot disk message. I first suspected the harddisk, connected it to a MacBook Air, and OS X Disk Utility identified the 2.1GB disk correctly and found the file system clean. Reinstalling it changed nothing.
The laptop did boot from its original 500MB disk, so the disk itself was not the problem. The real cause: disconnected from power for so long, the BIOS battery had run empty and the basic settings had reset, including date, time and the harddisk interface mode. Once I set the interface mode back to enhanced IDE, the machine booted from the larger 2.1GB disk again.