Create a junction path between two folders

Create-FolderJunction.ps1

# REMARK: By default UNC to local junctions are disabled
#         To find out run 'fsutil behavior query SymlinkEvaluation'
#         To enable run 'fsutil behavior set SymlinkEvaluation R2L:1'

$source = 'd:\folder-a'
$target = 'd:\folder-b'

Robocopy $source $target /MIR /R:12 /W:5

Invoke-Expression "cmd.exe /c attrib +r $source\\*.* /s"
Write-Host "Set source to read only"

Robocopy $source $target /MIR /R:12 /W:5

Write-Host "Moved source to $source-backup"
Move-Item $source "$source-backup" -ErrorAction Stop

Invoke-Expression "cmd.exe /c mklink /D $source $target"
Write-Host "Unset target read only"

Invoke-Expression "cmd.exe /c attrib -r $target\\*.* /s"