EDIT 7/19/20: Yes, revalidate first. Start Tequila --> Options --> Revalidate.
I have had this take a little time or get hung up on that 'one file' and never finish. However it is a good and potentially faster fix.
I also recommend leave 32 bit client behind and go to 64 bit if you can.
I stand by my old COH general fix - aka scorched earth
Find your directory where COH is installed on your computer for me it is D:\COH
delete COH install directory - it's ok, your characters, account and stuff is on a server on the internet
EDIT: There is a screen shot subdirectory if you take pics while in game you may want to back up.
I don't know if you can uninstall or just delete the Tequila/installer - get rid of that too. Mine is inside of the D:\COH folder and not another location
Empty the recycle bin
Reboot computer
Download a fresh new installer and let COH install again to a fresh install.
When people start getting into modifying .dll or messing with .net or other things I have no interest in that, but if it works for them - good for them!