Shrinking Windows Partitions
Many people want to install a Linux distro without wiping the installed Windows operating system.
A sane and less troublesome approach is to use a second hard disk. This is not always possible for many users, such as those using laptops.
Another option is to use a virtual machine. May modern computers have the hardware muscle to support virtual machines.
Many users with single disks still prefer to dual boot. The only way to dual boot on a single hard disk is to shrink the Windows disk space.
This can be done from the Linux Live ISO or installation disk using
gparted. I have done this only a few times. I have not had any scream moments resizing from Linux, but I am way more comfortable doing so from the Windows side.
Aggressively shrinking a Windows
C: partition should be done on the Windows side. Doing so from the Windows side also allows disabling
Fast Startup. Doing so allows temporarily disabling certain large immovable files, such as the swap and hibernation files, as well as native defragging.
After shrinking that partition,
gparted can be used to move exterior partitions, leaving room on the disk for Linux partitions.