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Is there a way to do a fresh install of Windows 10 on an empty drive with a larger EFI partition than 100MB (approx 200MB)? I plan to dual boot OS X and I want to avoid a certain issue that might pop up.
Extreme112
Posted 2017-02-07T17:55:25.270
Reputation: 11
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This is quite an old question, but I thought this knowledge would be useful to share since I spent a few hours digging for the answer.
It turns out you can manually create partitions during fresh install instead of relying on the automatic partition creation.
You can press Shift+F10 to start a terminal in the installation environment, then use diskpart to form the disk to your will. It has a built-in help system, and should be fairly simple to use.
I should include a disclaimer that this is potentially dangerous and can cause data loss, so make sure precious data is backed up before fiddling with partitions.
Information gleaned from: https://docs.microsoft.com/en-us/windows-hardware/manufacture/desktop/windows-setup-installing-using-the-mbr-or-gpt-partition-style
NOTE 1: (Gleaned from the built-in help) It should be noted that windows 10 requires a certain structure on a GPT disk to boot. On the disk from which you wish to boot, the EFI boot partition must be first, followed by the MSR partition, followed by data partitions. I was generous and gave MSR 20MB.
NOTE 2: diskpart spoon-feeds partition types to you: when creating a partition, you are given the option to create an EFI, MSR, or "ordinary" partition. The list can be displayed by running
help create partition
in the diskpart interface.
ithenoob
Posted 2017-02-07T17:55:25.270
Reputation: 1
That is something I am in the process of doing and finishing reading some stuff today. My first attempt failed two weeks ago. I think what I am gong to do is image my Windows 7, expand the efi, restore the efi partition from the Windows 7 install and install Windows 10, then restore the Windows 7 partition. – Rich Manson – 2017-02-07T18:37:39.757
You should be able to pre-partition the disk with an ESP as large as you like. If the Windows installer replaces the ESP if you create a disk with just the ESP, try creating a "dummy" partition somewhere later on the disk with some non-Windows partition type code. You can then change that to a Windows partition or delete it and expand the Windows partition into that space after you install Windows. – Rod Smith – 2017-02-10T17:27:49.783