On Saturday, 29 July 2023 01:29:59 BST Peter Humphrey wrote:
> Hello list,
> 
> I've been a loyal user of KMail for many years. (Loyal? Masochistic might be
> a better word.) It suits me exactly - or it would if it were reliable. It
> isn't, though, which drives me to consider alternatives.

I've been using Kmail since the good ol' KDE3 days.  Back then it worked at 
least as good if not better than any other mail client I had tried.  With the 
move to KDE4, Kmail became the worse mail client I have ever used.  I mean, 
*catastrophically* worse!  Both for the messages involved and for my nerves.  
Initially I blamed sqlite, which I was using as its back end for a season, but 
things were not much better with mysql.  At some point I tried postgresql, 
which was more robust.  Over the years the code matured.  For some years now, 
Kmail is quite stable.  There are still a couple of glitches with its GUI, 
e.g. the columns width has a mind of its own and recently its Korganizer 
sister application notifications cannot be snoozed for a short period of time, 
but overall it works without any drama.


> Claws mail is often mentioned hereabouts, and I'd like to try it, but first
> I'd need to export KMail's 20-odd-year maildir history to mbox format.

Among many other email applications, I gave Claws a spin.  A couple of months 
later I abandoned it, because I ended up spending more time trying to bend it 
out of shape to behave like Kmail (from keybindings, to layout, to 
attachments, etc.) than I was spending using it.  Soon, my attempts to change 
its behaviour hit a wall of non-adjustable hardcoded features.  I don't blame 
Claws for this, rather my brain which had been accustomed to work with Kmail.

The mbox single file format is something I tried to move away from since the 
90s, because as it grows in size it becomes more prone to corruption.  Losing 
one message may be tolerable, but losing the lot less so.  Sure, backups exist 
for a reason, but why accept architectural weaknesses if there is the more 
modern alternative of maildir?


> Is
> it enough to run KMail's Import/Export Data tool to do this? It should be,
> on the face of it, but I'm suspicious (consider me paranoid if you like).

I'll echo the recommendation for dovecot, plus backup(s).  If things go 
sideways during your experiment, you can rinse and repeat.  This is just good 
practice.

That said, I have used the Kmail Import/Export data tool in the past to move 
messages between Kmail and Thunderbird.  It worked, but can't recall the 
details.