Problems updating firmware from 1.50 to 1.51

I’m having problems upgrading my Digitakt from 1.50 to 1.51

I have downloaded the syx file to my local machine and am using Transfer 1.6.7

Initially I mucked up the process and forgot to select “OS Upgrade” on the device

I connected in Transfer and transferred the syx file, but it wasn’t installed

Then I discovered “OS Upgrade”, so I enabled that after connecting in Transfer, but now when I try and copy the file Transfer says “A file with the same name already exists in this directory”

How to I delete these existing files so I can complete the process?

I tried removing Transfer and reinstalling it but it gives the same message

TIA