I appears that the copy command is not quite right.
d:\internet\uacme\bin
>uacme -v newkey
uacme.exe: version 1.0.19 starting on Fri, 16 Aug 2024 00:11:40 uacme.exe:
loading key from /@unixroot/etc/ssl/uacme/private/key.pem uacme.exe:
fetching directory at https://acme-v02.api.letsencrypt.org/directory
uacme.exe: retrieving account at https://acme-v02.api.letsencrypt.org/acme/new-acct uacme.exe: account
location: https://acme-v02.api.letsencrypt.org/acme/acct/189418996
uacme.exe: loading key from /@unixroot/etc/ssl/uacme/private/newkey.pem
uacme.exe: /@unixroot/etc/ssl/uacme/private/newkey.pem not found
uacme.exe: generating new 2048-bit RSA key
uacme.exe: key saved to /@unixroot/etc/ssl/uacme/private/newkey.pem
uacme.exe: changing account key at https://acme-v02.api.letsencrypt.org/acme/key-change uacme.exe: backing up
/@unixroot/etc/ssl/uacme/private/key.pem as
/@unixroot/etc/ssl/uacme/private/key-1723792300.pem cp: cannot stat
'keyfile,': No such file or directory
uacme.exe: renaming /@unixroot/etc/ssl/uacme/private/newkey.pem to
/@unixroot/etc/ssl/uacme/private/key.pem uacme.exe: account key changed