Filepath.Walk in Go not picking up folders under C: drive properly in Windows

I am using the Filepath.Walk in Go to try to get all the folders under C: recursively. However it just returns me sub-folders starting with $Recycle.Bin. What am I doing wrong here?

package main

import (
    "fmt"
	"path/filepath"
	"os"
)

func main() {
	array := Subfolders("C:")
    for _,value := range array {
		fmt.Println(value)
	}
}

func Subfolders(path string) (paths []string) {
	filepath.Walk(path, func(newPath string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if info.IsDir() {
			paths = append(paths, newPath)
		}
		return nil
	})	
	return paths
}

Output:
C:
C:$Recycle.Bin
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R0L9M20
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R22ZOD9
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R3LS9P4
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R4T2IGU
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R8TZIET
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$R9QQZB9
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RA71HY3
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RBOC0V4.com
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RBOC0V4.com\go-fsnotify
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$REJFS3Z
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RF9A1Y6
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$ROMESWQ
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RP4CYID
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RQHMPV5
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RV0K99H
C:$Recycle.Bin\S-1-5-21-310629982-3373693989-3733510080-1000$RX54T04

I have many other folders under C: which donot get picked up by the filepath.walk. I wanted to understand what was the reason behind it.

EDIT

Thanks to the answers I was able to resolve the issue as below:-

func Subfolders(path string) (paths []string) {
	filepath.Walk(path, func(newPath string, info os.FileInfo, err error) error {
		if err != nil {
			log.Println(err)
			return filepath.SkipDir
		}

		if info.IsDir() {
			paths = append(paths, newPath)
		}
		return nil
	})

You're blindly returning errors without logging them. Returning a non-nil error from the callback is a signal for filepath.Walk to abort.

Presumably there is some file you don't have access to, or something.

You're returning an error, so it stops walking the paths. As the spec states, whenever an error is returned (besides one special case), processing stops. If you'd like to continue processing and ignore the error, just return nil instead.

Running it on my machine gives me an Access is denied error on one file, which then nukes the walk. The reason is only sees $Recycle.Bin is because it happens to be the first folder in the directory, and the walk is killed before it can get to any others.