Permission issue with hard drive

Hi, using thunar I noticed I was not able to delete some files in an internal hard drive I use as storage.

Looking at the permission tab in thunar of the files I cant delete it says that the owner is 1001. But if I unmount and remount the hd and right click on a file to see who owns it it says gregoire and it is only when I actually try and put a file in the trash or delete it that it refuses to do so and then displays 1001 as being the owner of the files. I have enabled Thunar Volume Management. I can still delete some files in the hard drive but not others, as in I can delete Barrylyndon.mkv in the the Barry Lyndon folder but I cant delete the-goodfellas.mkv in also in its own folder and they are both in the same “film” folder.

Any Thoughts ? Also maybe I shd make an other thread but I’d like to have a “mount iso” custom action in thunar but I dont know what command to put.

login on “su” and mark files with need name of user, not work?

It doesnt seem to, after doing chown the option to delete and move to trash is still greyed out, though my username is now dispalyed as being the owner in the permission tab in thunar. also I would like to make it so that this strange ownership behavior does not occur again.

plz show the Chmod command dialog on files. for examle in Midnight Commander

Deleting files is a write operation on the directory - so you need to have write permissions on the directory. Owner of the file is irrelevant.