@Jim McDonald
Thank you for your response, informations about your situation and also for your "condolence".
I can't understand APPLE to do this ISA-drama! What should I do as an user with encrypted images? Nothing? Waiting for the next incarnation of macOS? A few years ago Steve would have killed the software developers for such a thing.
I'm completely confused about the fact, that this will be happen with my old images (created with 10.6.8), but also with the new images (created with 10.14.6). Did nobody tried it in Cupertino? Or I'm wrong and make rookie errors.
BTW:
Since many years I did change my APPLE computers and also the operating systems only "with big jumps". Bought all my hard- and software all at once, spent time to bring all this little things to work and hope it'll work for a long period. I do not feel like spending my time with the computer itself (even this thing is a Mac), but do my work.
My first Mac - a Macintosh LC II in 1992 - survived more then 10 years. In times without internet - no problem. Later not less then 5 years, may be 5 to 7 years. So I did stand with my PowerMac 2012 until last month. For me: Best Mac ever. Very little problems, nice user interface and "the good old Mac-feeling". Does anyone think of the old clientele, but only of the new, young costumers? Yes, we are getting older too, but we are loyal!
In this year in June I bought 4 brand new Mac mini and I looked hopeful in the future. The bigger the surprise about the trouble with so many thing:
• old Time Machine Backups didn't work and I've to use "do it yourself style"
• have to migrate my "Mail" by hand
• Photos is an overloaded chimera of iPhotos and Aperture
• Finder forgot icons that I had changed (aliases)
• colors are very important in human nature ---> grey is trendy, but not so good distinguishable
• Finder is not so responsive, but maybe I'm to stoopid to set all this little flags correct ---> but so the Mac is never the smart thing from earlier times
• and - last but not least - the "Iconserviceagent drama"
Yes, I'm not a deserter to "the dark site of the force", but APPLE makes my life harder for me than it has to be!