can you post here the exact type of enclosure you are using? are you connected to the USB 2.0 port?
the file permissions can be fixed easily by right-clicking the drive. properties. security. and setting the users/groups as follows. also remove any thats not in the list
(but before that lets fix your slow file access first since this will take a long long time with your current problem):
actually just go ahead and do the file permission fix first. if your enclosure supports USB3.0/3.1 or UASP connection. be sure you are connected to the USB3. not the USB2 port.
I fix the permission part and now i can access the files easily. So Much Thanks!