Arch Linux

jwhendy

Member

Registered: 2010-04-01

Posts: 621

Windows partition utility does not agree with fdisk

The background for this is here. Tl;dr: I created 3 primary partitions (SYSTEM, C:, shared data) and two logical (/boot and /) for a dual boot system, and ran into issues with chainloading from win7 with EasyBCD. To troubleshoot, I simplified the setup to 3 primary partitions, and am now trying to go back... but can't!

Method:
- Delete all volumes/partitions after C:
- Create primary partition of ~100G, NTFS formatted (shared data)
- Create logical partition of 256M, unformatted (/boot)
- Create logical partition with remaining space, unformatted (encrypted /)

I used the built-in win7 partition utility for this, and it looks like it worked: screenshot

My first alert was the fact that Minitool Partition Wizard didn't agree with win7: screenshot

In fact, trying to create logical partitions with Minitool reports that the operation was successful, but as soon as it completes they turn back into unallocated space. I actually tried this first and then went with the win7 utility as I thought something was wrong with Minitool. I'm starting to think it's the other way around and that Minitool sees the correct state and win7 is wrong. That diagnosis comes from the output of fdisk via booting an Arch installation image:

Invalid flag 0x7d9b of EBR (for partition 5) will be corrected by w(rite).
Disk /dev/sda: 238.5 GiB, 256060514304 bytes, 500118192 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x1e6513b3

Device     Boot      Start        End    Sectors   Size Id Type
/dev/sda1  *          2048    2101247    2099200     1G  7 HPFS/NTFS/exFAT
/dev/sda2          2101248  172433407  170332160  81.2G  7 HPFS/NTFS/exFAT
/dev/sda3        172433408  387473407  215040000 102.6G  7 HPFS/NTFS/exFAT
/dev/sda4        387473408  500115455  112642048  53.7G  f W95 Ext'd (LBA)
/dev/sda5       2961659748 5859253686 2897593939   1.4T 65 Novell Netware 386

No idea whatsoever on the type ID assigned to /dev/sda5, nor why it shows as 1.4T. I've tried various things with no success:
- check/fix errors via win7 drive properties (no errors found)
- delete all non-win7 partitions, grow the partition to the full disk, and then shrink back again
- shrink win7 to ~80G, create a single primary partition, boot Arch install media, format with ext4, `dd if=/dev/zero of=file.txt` until full, then delete file
- change order (2 logicals, then primary)
- format the logicals with NTFS upon creation instead of leaving them unformatted
- assigning drive letters upon creating the partitions vs. no drive letter

I'm hesitant to just do everything from fdisk, as I have McAfee Endpoint Encryption and I'm not sure if writing the partition table from outside of windows can possibly ruin anything related to how the startup decryption works. If someone can assure that dd'ing some number of bytes on /dev/sda would allow me to reverse the process (restore said bytes to the beginning of the drive) in the event of any failures, I'd be willing to give that a shot. I know I've dd'd the encrypted MBR in the past and successfully restored it (after trying to install grub instead of the windows bootloader) just fine and been able to boot again. Not sure if messing with the partition table is any different.

Thanks for any suggestions!

boban_dj

Member

Registered: 2015-03-17

Posts: 150

Re: Windows partition utility does not agree with fdisk

You should leave open an unformatted partition, which windows will not recognize, then partition it with gdisk or fdisk from the Archlinux install.
Setting the `/` or `/boot` in windows will format it in a Windows specific way.

You can use grub2, create small bios (ef02) partition and dual boot from grub2. Much easier in my opinion.
In gdisk you can find the `ef02` option for type of partition. (I am not sure about fdisk)
Windows is not made for dual booting except for Windows.

Last edited by boban_dj (2015-07-15 08:50:52)

jwhendy

Member

Registered: 2010-04-01

Posts: 621

Re: Windows partition utility does not agree with fdisk

@boban_dj: I'll look into that. Had never heard of a BIOS partition before!. I would disagree with your last statement, as I wrote this wiki entry some years ago and it's worked for me up until this most recent laptop. Thus, I think it's related to McAfee Endpoint Encryption v 7.x (vs. 6.x and earlier on other computers I've had). EasyBCD has worked great up until now.

That said, I can definitely try your suggestion. If it was't clear from the above, my aim was for a shared partition (Truecrypt / NTFS), so I needed some WIndows readable format. For my actual Arch install stuff, I did exactly as you suggested, namely creating the partitions but leaving the format raw and formatting from the Arch install media.

This post was sort of updated by this one. Basically, whatever Arch or Minitool does isn't agreed upon by the Windows system partition manager, and vice versa due to McAfee automatically encrypting any partition from Windows (unless it doesn't have a drive letter or isn't a Windows format). Thus, my Arch install is just fine as it's off the radar.

For dual booting, what I'd really like to do is this. Install syslinux to /dev/sda and get it to chainload a backup of the current encrypted Windows mbr.