Re: move kmail to new computer
If the USB drive has a Windows file system, then perhaps there's some sort of incompatibility.
Personally, I would make a tar archive on the old system, then unpack that on the new.
On the old system
Code:
cd $HOME
tar zcf /media/LACIE/kmail.tgz .kde4/share/apps/kmail
On the new system:
Code:
cd $HOME
tar zxpf /media/LACIE/kmail.tgz
but check whether the USB mount name is correct in both cases.
openSUSE Leap 15.4 Beta; KDE Plasma 5.24.4;
testing Tumbleweed.