01
Mar

Fixing Windows 7 boot failure after changing active partition

This morning I was farting around with Windows trying to remove the write protection on my new SSD that I have connected to my HP Elitebook 820 over USB3. While doing that I accidentally selected the "Mark Partition as Active" on the external (D:) drive. At the time I didn't realize what this meant and it didn't give me a warning prior. In trying to undo this, I tried to mark C: as active. This time it warned me and said I was in danger of breaking the bootsequence of Windows. OK.... decision time. Do I take the red pill or the blue pill? I'm pretty sure keeping my accidental "Mark Partition as Active" on the D: drive hosed my boot order even though it did't warn me (in retrospect I probably should have tested this assumption first). So, I needed to do something. Do I pick C: and heed the warning? I know Windows is on C:. I picked C: and decided to reboot. If this hosed me I wanted to deal with it now vs. next week when I'm on the road for business.

Fail... Windows won't boot. I should have picked the System Partition as the active partition (the blue pill).

Below is what I did to fix it.

Get a Recovery Disk/Repair Tools

My many years of being on the road as a consultant or traveling to one of our offices has taught me to be prepared for disaster with as much as you can fit in your laptop bag without breaking your back. I carry USB thumbdrives with Bootable images of all the OS's I care about. If a hard drive dies on me, I can get an OS on it in minutes. If you don't have one of these - get one. All you need is a 4GB+ USB thumbdrive which are dirt cheap these days. From there, download the ISO of the OS(s) you care about and use the Windows 7 USB/DVD Download Tool to copy the ISO to the thumbdrive and make it bootable. This is useful not only for installing Windows as a new drive, but with the installation disk Microsoft provides the repair and recovery tools. The latter is what I needed to fix this

Boot into the ThumbDrive

This is different with every machien of course, but for my HP BIOS, hitting ESC on the boot sequence allowed me to force it to boot from the thumbdrive. From there, you Next through new install screen and select the Repair Tools link. You'll then need to pick Command Prompt

Use DISKPART to fix the active partition

  • X:\sources>DISKPART
  • DISKPART>SEL DISK 0
  • "Disk 0 is now the selected disk."
  • DISKPART>DETAIL DISK -- this will give you a report of volumes available on your disk
  • SEL VOL 0 --or whatever your system partition is
  • ACT -- sets it as active
  • EXI -- exits

Close the command prompt and reboot (remove the thumb drive)

Hope this helps someone else out there taking pills....

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