testing (stretch): Partition disks Guided - set up encrypted LVM-- failed

[nice sw123 <nicesw123@gmail.com>]

Hi,

I would like to install testing (currently stretch) on a machine, with
disk encryption.

During the part called
* "Partition disks"
I choose
* "Guided - use entire disk and set up encrypted LVM"

then I continue (I select SCSI1) and then
* "All files in one partition (recommended for new users)"

then I select <Yes> (regarding "Write the changes to disks and configure LVM").

AND THEN IT ALL FAILS HORRIBLY:
I get:
"Configuration of encrypted volumes failed"
"An error occurred while configuring encrypted volumes."
"The configuration has been aborted."



Is this a known issue? Or is the problem on my side? (in which case:
what am I doing incorrectly, what should I do?)
If "known issue": is there a workaround?

Is there a nice guide somewhere, how I'd go about setting up LVM and
encryption manually (during installation), to get a good default? I'm
currently not interested deeply in this topic... thus I just want some
encryption and a sane easy setup of partitions (e.g. all files in one
partition); and would thus appreciate a easy cookbook/tutorial style
guide. Available somewhere?

Thanks.
n.