System reserved partition not created

Hello,

When originally installing Windows 7 Ultimate I noticed it created a 100mb system reserved partition. No probs.

Recently I turned on AHCI in my bios and attempted to do a clean install. This time WinPE did not create a reserved partition and despite creating an 80gb partition to install windows on it said “Setup was unable to create a new system partition or locate an existing system partition.”

Install refused to proceed any further, pointing me to some log files I could not find. I booted from my repair disk and tried to make the partition active, which was already marked as active and tried again. No luck.

I had deleted all partitions on the drive.

So I turned off AHCI and tried again. I missed the "press any key".. and system complained about a "Master boot record error".. I rebooted and tried to do install again. Same issue.

I was able to recover my system from an image I created earlier, but I sure would like to know why the reserved partition was not created, and why windows refused to install. Because I'm going to try again.

I have purchased a new HDD, one that is supposed to be much faster than my old one, which of course has not been formatted. I tried that drive with and without AHCI and had the sasme issues.

If you have partitions defined beforehand it will not offer the Win7 100mb System Reserved partition. Wipe the HD and it likely will.

There is a way to get out of it during install, by deleting the Win7 partition and expanding the 100mb partition it creates to install Win7 there.

The easiest way to wipe and/or format the HD ahead is to boot into the Win DVD repair console, open a Command Prompt and type:

DISKPART
LIST DISK
SELECT DISK # (for Windows 7 disk)
clean
create partition primary
select partition 1
assign letter=c:
active
format
exit

Now you are ready to boot back into the Win7 DVD, select Custom install and install Win7 without the System Reserved partition.

If on the other hand you want the System reserved partition, just run Diskpart through the Clean command, exit and begin Custom installation using Advanced drive tools to create New and format.

There were no partitions on the drive - it was brand new.
Yes, I wanted the 100mb partition.
The CLEAN option resolved the issue.

thanks