Windows 10 Creating recovery drive on 4gb usb stick

The USB requirement vary with your Windows version. If your are using Windows 10 32-bit than a 4 GB USB stick is sufficient. But for a Windows 10 64-bit system I will advice you to use a 8GB stick.

Note: Recovery drive feature only works with a USB stick.

If you want to use a DVD, then create a System Image instead.

A 4GB USB stick will never provide 4GB worth of storage space.

I'm unsure the exact size of the WIM and boot/recovery files but they're often bigger than the average 4GB stick average capacity in total.