Started kmail from console, no error or message shows when trying to check mail (Ctrl-L).  Pasting results, as some messages seem relevant.

[michael@localhost ~]$ kmail
QObject::connect: Incompatible sender/receiver arguments
	KMFolderMgr::msgRemoved(KMFolder*,Q_UINT32) --> KMMsgIndex::slotRemoveMessage(Q_UINT32)
QObject::connect: Incompatible sender/receiver arguments
	KMFolderMgr::msgAdded(KMFolder*,Q_UINT32) --> KMMsgIndex::slotAddMessage(Q_UINT32)
QObject::connect: Incompatible sender/receiver arguments
	KMFolderMgr::msgRemoved(KMFolder*,Q_UINT32) --> KMMsgIndex::slotRemoveMessage(Q_UINT32)
QObject::connect: Incompatible sender/receiver arguments
	KMFolderMgr::msgAdded(KMFolder*,Q_UINT32) --> KMMsgIndex::slotAddMessage(Q_UINT32)
WeaverThreadLogger: thread (ID: 2) suspended.
WeaverThreadLogger: thread (ID: 1) suspended.
WeaverThreadLogger: thread (ID: 3) suspended.
[michael@localhost ~]$ WeaverThreadLogger: thread (ID: 4) suspended.
Weaver dtor: destroying inventory.
WeaverThreadLogger: thread (ID: 1) destroyed.
WeaverThreadLogger: thread (ID: 2) destroyed.
WeaverThreadLogger: thread (ID: 3) destroyed.
WeaverThreadLogger: thread (ID: 4) destroyed.
Weaver dtor: done

[michael@localhost ~]$

My initial guess would be that the pop3 kioslave is not installed or cannot be found on your system.  Try launching the pop3:// kioslave in konqueror, and if that fails as well look for missing pop3 kioslave .desktop and/or .so files.

> Try launching the pop3:// kioslave in konqueror

Error:  Protocol not supported  pop3

> if that fails as well look for missing pop3 kioslave .desktop and/or .so files.

You've gone well beyond my level of skill to understand what you just requested.

I can do this, so I did:

[root@localhost ~]# yum provides \*/kioslave

http://pastebin.com/JEQfm2yq

which, ignoring the checksum prob.s again, shows kioslave in a ton of packages, so:

A) Do I already have the proper package installed, but there is a pathing issue (as in http://bugs.pearsoncomputing.net/show_bug.cgi?id=809 )?  If so, what specifically do I need to change, to pick up the correct kioslave?
B) If not A), What package do I need to install?
C) If not A), Shouldn't this package be a dependency of trinty-base / trinity-pim (or whatever package kmail is part of)?

Thanks Tim,
Michael

(In reply to comment #3)
> > Try launching the pop3:// kioslave in konqueror
> 
> Error:  Protocol not supported  pop3
> 
> > if that fails as well look for missing pop3 kioslave .desktop and/or .so files.
> 
> You've gone well beyond my level of skill to understand what you just
> requested.
> 
> I can do this, so I did:
> 
> [root@localhost ~]# yum provides \*/kioslave
> 
> http://pastebin.com/JEQfm2yq
> 
> which, ignoring the checksum prob.s again, shows kioslave in a ton of packages,
> so:
> 
> A) Do I already have the proper package installed, but there is a pathing issue
> (as in http://bugs.pearsoncomputing.net/show_bug.cgi?id=809 )?  If so, what
> specifically do I need to change, to pick up the correct kioslave?
> B) If not A), What package do I need to install?
> C) If not A), Shouldn't this package be a dependency of trinty-base /
> trinity-pim (or whatever package kmail is part of)?
> 
> Thanks Tim,
> Michael

I'm sorry I can't help much with RedHat/Fedora.  I do know POP3 works on Debian/Ubuntu, so this is likely an issue with the RPM packaging.  Therefore, I have added Francois Androit to the cc list on this bug so that he will be made aware of the problem.

Thanks Tim,

I would have to believe that this normally works (would seem strange I'm the first to want to use kmail), and maybe that last build has a typo?

Hi Francois,

This is a migrated kmail.  Following these instructions (built my own as I couldn't find any):

michael_centos62	Hi all, kmail problem.  Anyone know where/how to move the kmail identities from kde4-kmail to trinity-kmail?  All the messages copied over fine, but not identities :(
*** aalecs has joined #trinity-desktop
michael_centos62	pasting the answers to my questions so it's searchable on the irc log
michael_centos62	migrate kmail identities: copy ~/.kde/share/config/emailidentities to ~/.trinity/share/config
michael_centos62	migrate kmail messages/emails:  copy ~/.kde/share/apps/kmail to ~/.trinity/share/apps/kmail
michael_centos62	migrate kmail accounts:  located in ~/.kde/share/config/kmailrc sections [Account ##] and [Transport ##].  (suggestion is to manually recreate them, rather than copy and paste the sections, as no telling if KDE4-kmail syntax is valid with trinity-kmail syntax)
michael_centos62	migrate kmail:  helpful with other file locs.  http://userbase.kde.org/KMail/FAQs_Hints_and_Tips
michael_centos62	migrate kmail another tip:  You can manually merge all your different machines' kmail directories (~/.kde/share/apps/kmail) into one and copy that to ~/.trinity/share/apps/kmail , trinity-kmail will then re-index them all once you (re)start it.

Did I overwrite some file I shouldn't have?  Although I did all the file copies before running trinity-kmail for the first time.

Oh, nevermind the above.  I also tested this on a just built user, same problem, even when kmail is run from scratch.

Best,
Michael

Hello, try to install (if not already done) the following package :
trinity-kdebase-pim-ioslaves

Then try again kmail, and tell me if it works :)

Yeah!

trinity-kdebase-pim-ioslaves was not installed, installing it fixed this.

I installed Trinity with "yum install trinity-desktop" and nothing else.  I'll somewhat guess, pim-ioslaves needs to be a dependency of trinity-desktop?  

In any event, I'll leave this open and let you close it as needed for the pim-ioslaves resolution.

Thank you Francois,
Michael

Footnote:
Updated https://www.centos.org/modules/newbb/viewtopic.php?topic_id=37706&forum=55 with resolution.