I had a crash in Kubuntu 22.04 with Thunderbird (up to date 115, German language). I set a Master password for Thunderbird. I installed then Kubuntu and Thunderbird again and Thunderbird without Master Password. I have a backup of the private email key (*-secret.asc exported from Thunderbird!), but it is not possible to import the private key. All I get is „Failure File can not be imported“. What is the problem and how to solve it? I did new installations (without master password) before and it worked. It’s a really big big problem for the email system if the (Backup) keys can not be imported after crashes or new installation of the system.