gpg: KEYTOCARD failed: Unusable secret key

[Felix E. Klee]

On Tue, Jul 26, 2016 at 1:22 PM, Andrew Gallagher <andrewg at andrewg.com>
wrote:
> If you want to keep a backup copy on local disk, you need to quit
> *without saving* immediately after running 'keytocard'.

Hitting <Ctrl-C> to quit did the trick. Now I could copy the key – a new
one – to two cards. Thanks for the suggestion!

Before that I tried re-importing the private key from the `.asc` file,
but it still was not possible to write it to another card. The error
message was the same as before. I don’t understand this: The key is
around, but somehow I cannot use it.