Remove percentages from robocopy log

/njh and /njs have nothing to do with the percentage information. You need to suppress progress output by adding the option /np to your robocopy commandline.

From the documentation:

/np Specifies that the progress of the copying operation (the number of files or directories copied so far) will not be displayed.

Edit: After taking a look at your actual commandline it looks like /np is not compatible with /mt. Adding the latter parameter makes robocopy display progress output even if /np is present. If you don't require running multi-threaded I'd remove that parameter (add /ndl to prevent directories from appearing in the output).

I would also recommend using splatting instead of putting the parameter list into a single string:

$params = $src, $dest, ('/LOG:"{0}"' -f $logpath), '/L', '/NP', '/NC', '/BYTES',          '/NJH', '/NJS', '/NDL', '/E', '/MOVE', '/XC', '/XN', '/XO', '/XD',          $excludedFoldersList& robocopy @params

If for some reason you must use multi-threading you should be able to remove progress information from the log after completion like this:

(Get-Content $logpath) | Where-Object {    $_ -notmatch '^\s*\d{1,3}%\s*$'} | Set-Content $logpath