- No way of setting up Thunderbird mail folders, one cannot put mail onto SD card as the default.

- Where's all the options such as leaving mail on the (POP) server?

- When in Manual setup K-9/Thunderbird downloaded mail before I had a chance to select never in accessing mail. Doesn't manual mean just that?

- K-9/Thunderbird wants to sync things by default. Can't people at Mozilla realize that the main reason for using this package is that we do not want a repeat/rehash of Gmail! In simple English that means:

We want nothing to do with Google in anyway whatsoever!

Moreover, on some of my rooted phones there are no Google apps—not even their non-spying equivalents such GApps or MicroG which means the mailer must work all by itself as on the PC. It's people like me who will use K-9/Thunderbird, the great unwashed will nearly always continue to use Gmail, so there is little point in developing an email client for Android unless it significantly differentiates itself from the default Gmail.

- K-9/Thunderbird assumes one will give it access to one's contacts (I don't), it has no alternative to Android Contacts. Why doesn't it have its own address book? It's really annoying when it nags about not having access to Contacts. Other privacy-focused Android apps use both Google's and their own address repositories, so why not K-9/Thunbderbird?

- The editor in Thunderbird for the PC sucks big-time (I've whinged about this for years), this one in K-9/Thunderbird could hardly even be called an editor, it's only really an SMS messenger text handler it's so primitive. I know, many just want a basic or ASCII-like text editor—and it seems so do Thunderbird's developers (developers you are developing for others not just yourselves). Remember also that Android encompasses more than just smartphones, tables etc. which I use with a Bluetooth keyboard and mouse (K-9/Thunderbird under these circumstances looks and works like something out of the Dark Ages)!

If you cannot fix the editor then allow users to use an external one!

- Where's the multiple accounts setup (if it's there then Mozilla you've done a good job at hiding it)?

Three days ago I had to set up Thunderbird for the PC Windows on a new laptop and it was a damn time-consuming pain. Transferring email from one PC installation to another is something that obviously Thunderbird developers never do (probably because they're all using Gmail and The Cloud on their phones, thus they never have to bother). To make matters worse, I've promised to do the same for a colleague who cannot do so and I'm dreading the fact.

To put this K-9/Thunderbird offering into perspective, it's worth considering what is wrong with the PC version—and here I'm not talking about some old version but the latest 102.5.0 and current beta 108b2. That's a tall ask because it'd take many, many pages to describe the problems adequately, so I'll just outline a couple problems that bug me and others (common ones collected from help desk logs, etc.).

- Thunderbird, like Firefox, has made a reputation for busting add-ons/plug-ins; every new version busts something, and it's invariably done in the name of security. Instead, of Thunderbird's developers either sandboxing add-ons or provide an option 'add this add-on at your own risk', they take the approach of an authoritarian dictator and simply kill any of them that doesn't take their fancy—then, as so often happens—the only plug-in that does a specific job no longer works (this is yet another example of why software development can't rightfully be classed as true engineering—real engineers don't take away, say, steps from a building after installation so people cannot use it!).

What developers of both Thunderbird and Firefox forget is that the main reason why users install add-ons to these programs is to overcome basic and often very fundamental limitations in their design in that they are missing when they ought not be, these fixes are often considered essential to users often more so than than security considerations/fixes (it's certainly so with me). We find it very annoying when some important feature goes missing in an upgrade. Furthermore, Mozilla developers rarely bother to placate irate users, their arrogant 'it's-free-so-don't-bother-us-with-your-problems' attitude means one doesn't even get a hearing when one complains.

- Thunderbird has a 'feature' that allows the user to change or add profiles called profilemanager. You'll never find it in the menus because it's just not there. Instead, after searching or fossicking around on the web you'll find that this cryptic, poorly-explained feature can only be reached from a 'switch' on the Command Line—yes you read correctly the Command Line! Until recently, if you deleted an old profile then you also deleted your mail files folder and even now it's still quite possible to do because it's a horrible, ergonomically unsound, bit of afterthought coding that's hung around like a bad smell for years (yes, like other boring but essential bits of Thunderbird it's not been fashionable enough to re-code and or fix it).

The ergonomics of Thunderbird's profilemanager is so terrible that I'd like to see the culprit(s) in the stocks for a few days so everyone got to know those who make a crime out of coding. All future versions of their CVs with the fact compulsorily entered therein would round it off. The profilemanager only does part of the job, one has to go into the Accounts management and manually patch the directory where one's mail is located (that is unless it's in the default location). Anyone who has to set up multiple accounts and has to have the mail on different drives and or in different directories can spend hours trying to sort out the many problems. Multiple accounts are all jumbled up in the prefs.js file, and just looking at it one can immediately see adding multiple accounts was also an afterthought. The obvious thing to do would have been to separate these accounts into separate files then one could move them about to different machines etc.—even for maintenance it would save a great amount of time.

Looking at the 'time modified' timestamp on my files I note that it took me 7 hours and five minutes to reinstall the accounts on the new machine (BTW, there are only four accounts involved, I didn't have time to do them all at the time).

- Much time is wasted installing Thunderbird because developers think it's a good idea to ensure that you cannot set up mail offline! If you want to set up mail manually, and you have all the server parameters tough luck—you have to have an internet connection. Yes, I know mail setups have to be completed online but if one could set up the mail account offline beforehand then it'd be only a click or two when one went online. The question is why hasn't this nonsense been fixed years ago.

- Moreover that first account becomes the main account and heads the tree whether you like it or not (as it's the first account it's likely to be used more often and likely mistaken (very problematic if one gets one's work and home accounts mixed up)). The only way I know to change it is to set up the main account then 'nuke' it later. After checking that the account works shut down Thunderbird and edit the prefs.js file with dummy information (it's tedious as there are multiple entries). The dummy account I created is no.mail@default.nul. After that recreate the original account, it will now be further down the tree. If there'd been a competition to make it harder for the user then Thunderbird developers would have had difficulty beating their efforts with such stupid shenanigans as we've seen here. To put it bluntly, Thunderbird's ergonomics and program design is a fucking shambles and no amount of dressing it up with new features will fix it. What's needed are bugs and limitations fixed first.

One quick point to finish: the mail editing window cannot be docked with the main window. Why the hell not? If this is considered undesirable then just have it as an option for those who want it.

There's so much wrong with Thunderbird that I sometimes wonder if Microsoft employees are working for Mozilla as Trojan horses! What better way to bring open software into disrepute. And the proof's seems to be in the pudding: in recent years with Mozilla developers doing what they damn-well please instead of fixing bugs and boring but necessary work, it's little wonder Mozilla has fallen from grace.

Many others and I would be very happy if Mozilla offloaded Thunderbird onto others—those who know what they're doing and who actually understand what users want from a modern email client.