PowerShell: "Move-Item : Cannot create a file when that file already exists." - powershell

Question

The code below has been wonderful so far for organising my hard-drives.
I do face this error when I transfer large amounts of data:
Move-Item : Cannot create a file when that file already exists.
This happens when I move a file that is duplicate, is there a way to rename the duplicate file in some sort of sequence?
That would be much appreciated :))
# Get all files
Get-ChildItem "C:\zAa" -File -Recurse | ForEach-Object {
# Get the modified date
$dt = Get-Date $_.LastWriteTime
$year = $dt.Year
$month = $dt.Month
# This adds "0" in front of the 1-9 months
if($dt.Month -lt 10) {
$month = "0" + $dt.Month.ToString()
} else {
$month = $dt.Month
}
# Remove leading '.' from the extension
$extension = $_.Extension.Replace(".", "")
# Where we want to move the file
$destinationFolder = "C:\zBb\$extension\$year\$month\"
# Ensure full folder path exists
if(!(Test-Path $destinationFolder)) {
New-Item -ItemType Directory -Force -Path $destinationFolder
}
# Copy/Move the item to it's new home
Move-Item $_.FullName $destinationFolder
}
I haven't been able to do much, I normally go find the duplicates and rename them manually.

Answer 1

Probably the easiest way to move a file with a unique name is to use a Hashtable that stores the filenames already present.
Then a simple loop can add a sequence number to its file name until it is no longer found in the Hashtable.
Next simply move the file under that new name.
Your code modified:
# Where we want to move the file
$destinationFolder = 'C:\zBb\{0}\{1:yyyy}\{1:MM}' -f $_.Extension.TrimStart("."), $_.LastWriteTime
# Ensure full folder path exists
$null = New-Item -Path $destinationFolder -ItemType Directory -Force
# create a Hashtable and store the filenames already present in the destination folder
$existing = #{}
Get-ChildItem -Path $destinationFolder -File | ForEach-Object { $existing[$_.Name] = $true }
# Get all source files
Get-ChildItem "C:\zAa" -File -Recurse | ForEach-Object {
# Copy/Move the item to it's new home
# construct the new filename by appending an index number in between brackets
$newName = $_.Name
$count = 1
while ($existing.ContainsKey($newName)) {
$newName = "{0}({1}){2}" -f $_.BaseName, $count++, $_.Extension
}
# add this new name to the Hashtable so it exists in the next run
$existing[$newName] = $true
# use Join-Path to create a FullName for the file
$newFile = Join-Path -Path $destinationFolder -ChildPath $newName
Write-Verbose "Moving '$($_.FullName)' as '$newFile'"
$_ | Move-Item -Destination $newFile -Force
}