We’ve had a problem where files uploaded through the modx file manager (running Windows/IIS) were inaccessible via the web due to a permissions problem (e.g. http 401 error). I wasn’t able to find a solution online, here or elsewhere, so I thought I’d share:
It seems the uploaded files inherit the permissions of the temp directory (specified by php config’s "upload_tmp_dir") into which they initially land. Changing the permissions on the temp directory solved this problem for us.