powershell - robocopy/List option not kicking back folder access denies - windows

Question

Edit: Also, the reason I'm not using logging via Robocopy is that it doesn't seem to want to work with /MT: either. All I get is a start and finish status using robocopy logging.
Below is my current script for finding specific files on a network via robocopy. It works perfect, especially with the multithreading. However, I am searching network shares, and occasionally, I come across a directory that I do not have access to. Robocopy seems to have some ability to kick back access denied messages, but I have not been able to get them to work with the /L option. /MT: also sometimes tends to do some weird things to the output. /V (verbose) has no effect on the output when combined with /L.
Without /MT: set, I am able to slowly get all directories and files listed. However, if I am denied access to a particular directory, the output will only show the parent directory where I am initially denied.
If I enable /MT: I am still able to find files and folders, however, the log then doesn't output the top parent directory in a path where I am denied access.
Robocopy is my only option due to longpath problems with DIR and Get-childitem. It also so far has worked the fastest out of all the options due to threading.
Permissions are not changeable, and I do NOT have backup administrator rights to override ACL denies.
If anyone knows how to capture the deny/failure logs, or has a clue, I'd be super happy. I know I have denies because the bottom of each log will list how many times it failed. But if it's listing how many times it failed, surely there's a way to write each time individually to a log?
To set up an artificial fail at home, I used a standard account to run ISE, and using my admin, created a directory with some files, and then another subdirectory inside, removing all permissions for everyone for the subdirectory and files inside it, and changed the owner to system. All the files showed up, however, the subdirectory only showed with the top folder, and was unable to search any deeper.
$ErrorActionPreference = 'continue'
remove-item C:\Users\$env:username\documents\log.txt
$measure= Measure-Command -Expression{
$path = "C:\Users\$env:username\New folder"
robocopy $path null /V /L /E /FP /XJD /XJF /R:1 /W:1 /MT:8 | % {
[string] $out=$_;
if(!($out.Contains("%"))){ECHO $out | Out-File "c:\users\$env:username\documents\log.txt" -Append}
} }
write-host $measure

Answer 1

/MT:x Definitely messes with output in a live copy.
I suspect the errors are going through the error stream (stderr), not standard output (stdout)
First I would add /np to your options. This way you don't have to deal with the "%" later.
Then try using redirection. I don't do it very often, but I think 2>&1 > will do it. It might look something like:
robocopy $path $FakeDest /V /L /E /FP /XJD /XJF /R:1 /W:1 /MT:8 2>&1 > "c:\users\$env:username\documents\log.txt"
Also, If you wrap this in start-process there are parameters to redirect both Standard and error streams. Again not tested but it might look something like:
Start-Process -FilePath C:\Windows\System32\Robocopy.exe -ArgumentList "$path $FakeDestination /V /L /E /FP /XJD /XJF /R:1 /W:1 /MT:8" -RedirectStandardError C:\temp\Errors.txt -RedirectStandardOutput c:\temp\Output.txt
Obviously change the file names...
If you really want to get crazy there's a module for NTFS permissions. It has cmdlets like Get-ChildItem2 these are based on a 3rd part API called AlphaFS (I think). it can access paths beyond the typical 260 character limit. I'm sure it will be slower, but failing the first 2 it may be worth it. I don't know how they react to access denied though...
I'm sorry I don't have time to test any of these approaches at the moment. However, do let me know if this helps at all. I'll be around...