I have successfully installed the 64bit version of MailCheck2: https://www.d-jan.de/download.shtml
Here is a link to the normal looking text-preview window: https://www.d-jan.de/img/shot2.png
I was also able to import the registry export successfully from WIN10. All functions work fine - even the deletion of mails server-side.
A text preview display problem remains. The text is rotated 90 degrees counterclockwise and runs in columns. Each letter individually from top to bottom. Does anyone have an idea? See attachment:
MailCheck2 - Text preview faulty
[Solved] MailCheck2 - Text preview faulty
The problem is solved. You only need to set a different font in the basic configuration for the message preview.