Solved Clean Install - Control size of Windows Partition during install

I'm doing a clean install of Windows 11 Pro on a new machine.
When I get to the part where there is just the one unallocated disk - if I select it and click next then the install process starts installing. No option to change the size of the C: partition.

I could click on "New" and create the partition size I want. Will the installer then create the other 2 partitions automatically?

What is the best way to get what I want?
Just install into the unallocated space and let it create the 3 partitions it wants, then shrink the partition with 3rd party software afterward? Seems clunky.

I recall in Windows 10 there was a way to change the size before it started going.

See step 11 in this tutorial and note that you can do NEW to create a partition from Unallocated space and also format etc. The capabilities are all there until you click Next.

As you say, if you just click next the installer will do what it needs. It will tell you if it needs to make the extra partitions.

Thanks. I will try that in the morning.

I am working with Brink's tutorial. It said to select the unallocated partition and then hit Next - and after that it says you can resize the partition. Semantics and a concrete mind I guess.

So I will create one new partition the way I want, highlight it as the partition to install Windows on, and then hit Next. And the installer will create the other two partitions automatically.

I thought it might, but didn't want to go through the whole installation to find out it didn't.

TVeblen said:

So I will create one new partition the way I want, highlight it as the partition to install Windows on, and then hit Next. And the installer will create the other two partitions automatically.

Click to expand...

Yep.
Just make sure you leave a bit of unallocated space for the EFI System and Recovery partitions.
Less than 1 GB will suffice. The installer "may" put those partitions on the space you selected for the install.
I'm not sure.
But if you leave 1GB unallocated... you're covered both ways.
If that 1GB doesn't get used, you can always get it back after the install is finished.

You can also... just use a program like Minitool Partition Wizard (free) to adjust the partitions however you want... after the install is done.
Like if you want to shrink the C:\ (Windows), partition down to say 200 GB... it's no problem with Minitool.


I just left the whole 500GB unallocated... then installed Windows and let it do whatever.
Then I used Minitool to arrange it the way I wanted...

In MY case... I removed the Recovery partition, and resized the Windows partition to 200GB.
Then I used what was leftover for some data partitions.




The stuff in the RED box is the minimum needed to boot Windows.

No matter which way you do it, make sure to unhook the other drives during the install.

The Windows installer has a tendency to put things like the EFI System and Recovery partitions, where ever it wants.
Even on other drives.




But if you plan ahead, like you're doing, you can make things.... pretty...





You can even get really creative...

Thanks Ghot. All good info. I'm going to install again this morning.

I had to use a partition management program to delete the partitions that the installer created and get back to unallocated space.
Odd that you can't delete those partitions in the installer - the options are greyed out when you go back.
I even got to the command prompt through "Repair My Computer" in the installer to use Diskpart and it would not delete the partitions.
And yes, I could have just created my own partitions while in the PM, but I want to learn to do in the installer and keep notes.

Funny, I know to disconnect the extra drives but apparently not yesterday. I got to the "Where to install" part and saw all the partititions and said something like "gosh darn it" (sort of) and had to start over. I've entered that Windows key 3 times already!

TVeblen said:

I'm going to install again this morning.

Click to expand...

Once you get everything set up and partitioned like you want... make a fresh backup with a program like Macrium Reflect or AOMEI Backupper.

Wow. That was amazing!
9 minutes from the point where I created the partition and hit Next to the Desktop.
And that is with me screwing around taking notes, and doing the SHIFT+F10 OOBE thing to get a Local Account.
I don't know if that is because of Windows 11 Pro installation or that monster rig.

So for anyone looking at this thread:
When you get to the "Where do you want to install Windows" window in the installer:

• Click "New" at the bottom
• Enter the size of the partition you want Windows installed on in MB (1024MB = 1 GB) > OK
• A message will pop up telling you that Windows will create some other partitions > OK
• Now you are back on the "Where do you" window with all 3 partitions showing, plus the unallocated space left over. You still have an opportunity here to create more partitions if you want. I leave that alone until I'm in Windows.
• Click Next and the installation begins.

@Ghot: I will be doing a disk image backup, but not right away. I spend a good amount of time setting these things up. It's on my workbench and I can go down and screw around with it a little at a time. I don't even introduce it to the internet until after I have installed all of MY drivers from the OEMs.
Very good advice however!