Find & delete leftover "dot underscore" files from macOS, using PowerShell on Windows.

mac-file-cleanup-dryrun.ps1

# log the -WhatIf output to a file for review
start-transcript c:\mac-file-cleanup.txt

get-childitem -directory |
  get-childitem -filter ._* -file -force -recurse |
  # filter out the items that don't have an accompanying non-dot-underscore file
  where-object { test-path -literalPath (join-path $_.directoryName ($_.name -replace '^\._','')) } |
  foreach-object { remove-item -literalPath $_.fullName -force -WhatIf }

stop-transcript

mac-file-cleanup.ps1

get-childitem -directory |
  get-childitem -filter ._* -file -force -recurse |
  # filter out the items that don't have an accompanying non-dot-underscore file
  where-object { test-path -literalPath (join-path $_.directoryName ($_.name -replace '^\._','')) } |
  foreach-object { remove-item -literalPath $_.fullName -force }