Got a simple fix for this which does two things:

1. Correctly act upon an error from the backup file writing
2. Print a warning note.

In T2169#196673, @werner wrote:

Shall we handle this with additional retry prompts, w/o a timeout? I think this makes sense because creating keys with a backup file and a passphrase is a manual task anyway.

There is a regression due to the regression fix in rGb30c15bf7c5336c4abb1f9dcd974cd77ba6c61a7 (from Dec 24 2015) or some related commits:

Closed, since this was documentation for the workaround, four years ago.

Just a reminder: with Gnuk 1.2.15 and an ed25519 key PubkeyAuthentication unbound is required for hosts using the new feature.

Fixed in 2.4.6.

I believe this was fixed by T7386. Or it is now no hard lock up by T7402.
So, let me close this ticket.
If any new symptom, please add information into T7396.

For this ticket, I reviewed the code around my SOS changes.
Because I'd like to focus the point of retaining binary representation when doing import->export,
I created another thicket: T7426

thanks for the clarification. i was not objecting to the workflow, i was trying to understand so that i can interact with the bug tracker appropriately. I was unaware of the difference between "milestones" and other project tags. I'll try to get that right in the future.

Please do not add milestone tags.

I put "scd" tag and let me claim this ticket.

For Beta-75 it looks similar judging from my first tries.

I managed to get the same "loading certificate" message several times in a row on this test instance by stopping and starting Kleopatra in a row twice. After removing the Signature Card 2.0 this did not happen again in 5-6 tries, although I collected 2 lingering listing processes again (not both started on the same startup). Even import of a X.509 certificate worked.

Next I managed to have one gpg and one gpgsm process each left over from the last execution of Kleopatra.
After starting Kleopatra new anyway, again "loading certificate cache" and an additional pair of gpg and gpgsm listing processes start.

Had a occurrence of the never ending "loading certificate cache" issue again.
There was a leftover gpgsm process from the previous tests (although Kleopatra warned when I closed it, that processes still running in the background were there and would be aborted).

@ebo Thank you for your continuous testing.

Unfortunately, this seems not to have ended the sporadic hangs.
I just saw a hanging initial keylisting with gpg4win-beta-70 which has gpg 2.4.6

Backported to 2.4 to go into 2.4.6

Fix backported to 2.4

Passing ticket to werner to consider backports.

Tested with VS-Desktop-3.2.94.2-Beta.
Works as expected on the cli.