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Gparted is implicilty converting my protective MBR to a hybrid MBR without asking me and without telling me, thus breaking everything I'm trying to do (making a NTFS partition that's accessible on Windows 7).

  1. After creating a new GPT partition table on a USB stick using Gparted (0.32.0) I can confirm with gdisk that the MBR is protective.

  2. After creating a new NTFS partition (with an identical label and partition name) with the same Gparted, I can confirm with gdisk that the MBR is now hybrid.

I didn't ask for a hybrid MBR, only for a new NTFS partition.

Gparted has been my go to partition editor for a long time, but this I find almost unforgivable. Is there a good reason why it does this?

There are no obvious technical limitations of why it can't leave the protective MBR alone, since gdisk had no trouble converting the MBR to a protective MBR after Gparted had ruined it.

Details

  • Macbook Air (2012) (no official support for UEFI)
  • Running Ubuntu MATE from a live USB
  • Gparted 0.32.0, operating on a 32 GB Sandisk Extreme

Result: unable to access partitions in Windows 7/10 until I manually convert from hybrid to protective MBR.

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GPT and MBR should always synced. If gparted would change only GPT, this could affect to discrepancy between GPT and MBR and cause data loss, when hybrid is used. It makes more sense then that gparted change it to hybrid after updating MBR. on the other hand hybrid is for read compatibility and does not affect accessibility. Your Problem might have to do with windows efi bootloader not allowing hybrid

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  • "GPT and MBR should always synced" -- not true; see Protective MBR. "It makes more sense then that gparted change it to hybrid after updating MBR" -- no, it makes no sense to introduce the very condition that is the root cause of the problem that you describe, as a solution to that very problem. "hybrid is for read compatibility and does not affect accessibility" -- it obviously affects accessibility since Windows 7 refuses to mount the volumes. – Sirap Apr 9 at 13:08
  • i agree it would better if gparted could differ - but it doesn't. from this position, updating only GPT is dangerous (for hybrid). but you can report this as bug. – alecxs Apr 9 at 13:25
  • As stated in the question, the MBR was never hybrid when making an update, so your point doesn't apply to this scenario. – Sirap Apr 9 at 13:36
  • Protective MBR is to prevent old partition tools (which cannot read GPT) from messing up partitions. Gparted is not such a tool - it can handle GPT. your questions was why Gparted change from protective to hybrid. Because every tool which changes GPT must change old partition table too (in case it exists). Gparted doesnt care about previous state of MBR, because it writes its own set of (consistent) partition tables (always GPT + MBR). Thats why it changes to hybrid – alecxs Apr 9 at 14:10
  • Yes, that's all well and fine, but: "Because every tool which changes GPT must change old partition table too (in case it exists)" I've already stated that "After creating a new GPT partition table using Gparted (0.32.0) on a USB stick I can confirm with gdisk that the MBR is protective". The "old partition table" doesn't exist. The MBR is protective. – Sirap Apr 9 at 14:25

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