AdiIRC

I'm not sure I understand the problem "same filename from difference channel" do you mean you are downloading to the same filename from multiple users?

When a new transfer is started, AdiIRC checks if the filename exists, and asks you to either resume or rename the filename of the new transfer, it doesn't care where it comes from.

Instead of quick connect, look into using the Serverlist, it has a proper Auth/password system.

1. Yes, you understand it correctly and what you say is what I expect it to be but it is not -yesterday (I deliberately test it yesterday).
I try it again now and it works as I expected (as you say) so I'm not sure now why it says 'INVALID DCC Get..' yesterday and I found it often with resume (100% every try). I must remove/rename the old file or select overwrite to download. Do you have any idea about 'INVALID DCC Get..' resume? I've no idea now but it would be good to know this failure cause.

2. Yes, I use 'Serverlist' because quickconnect has no password field. It just that I praise quickconnect is easy to use.
For the 'password not work' it seem I'm missing to select 'Login Method' to NickServ (it is too hidden, really). Thank to point some note.
*For the UI, I understand it is alphabetical order (a-z) now but it is hard for new-user really. I'm clumsy at first to set more about connection.
Like.. What menu sorting is this. Where to set connection. Then I go 'General', 'Server' and not found. Then I go 'quick connection' and 'advance..' which is it real place. But I just understand menu order this morning, I search it one by one before I know it is in alphabet order (menu start from 'away'), lol.
I naturally think the main option as 'connect' should lay at first item :P, as many IRC client, FileZilla(FTP), media player classic and most program come up to mind, usual lay their main option above. No problem with that, just tell about my UI experience.

It's hard to tell what exactly caused the "INVALID DCC Get", from what I can see, it only happens if a user sends a "DCC accept" or "DCC resume" and the dcc connection was previously aborted/shutdown or removed from the DCC transfer list.

I can see your confusion, but Quick connect is supposed to be limited and easy to use so there are no password or login method, if you need more advanced features, you go to the Serverlist.
There is links to Serverlist everywhere, even in the quick connect dialog at the bottom, you can also press CTRL + S or go to Menubar -> Server -> Serverlist, but I will think about making the Serverlist links more visible.

If you have any ideas on how to make Serverlist easier to find, I'll be happy to look into it.

Ps. There is a search box for Options in the top left corner, did you notice it? I tried to make it easier to see.

1.
So 'INVALID DCC Get..' cause is still unknown for sure? It's new for me (never happen in mIRC) so I freaking out.
But it is go away for now. I'm happy to help out anyway if there's log/something to be send to resolve this issue.

2.
For the UI, I fear to suggest more at first - I'm not sure if AdiIRC team will annoy for suggestion type or not. But it seem you guy happy to hear about it.
2.1
I really thought the main item should lay at top. If you want to maintain alphabetical order style. You may do something like separate section line***:

|-Quick connect

|-<some important option1>

|-<some important option2>

----------***

|-Away

|-Backgrounds

..so on as now..

The user will found what they usual deal with very easily.
*I double space there because if not, it will flip to the same line

2.2
To bring easier attention to serverlist sub-menu*** will very help about that, you may use it with other important advance too (that user often require to deal with), but dont have it too much as the list will too long.

|-Quick connect

|--Serverlist***

|-<some important option1>

|-<some important option2>

----------'

|-Away

|-Backgrounds

..so on as now..

*This will a lot easily kick the eyes. 2.1&2.2 will help you very much to promote very useful option that is hidden.

2.3 Search box, I just found it today too. For suggestion, you should make those red in 'bold' if it's not too much effort.
The box may be smaller a bit to make it distinct from below option list. And there's a top gap from the header a bit should help.
I understand that app may need to make out most profit from the compact space. But my eyes skip it at first because it is too high/close with above title so my feeling it is some comment/note (and I didn't read it even though it is red lol)
*The search job is good enough, I like it.

I am the only developer of AdiIRC and I'm always happy to hear about problems and suggestions, I will make note and think about what you suggested, thanks :>

Hello, I found this problem again. I still cant guess the cause. I try to restart computer and the problem still persist.
*Even found on same channel so that is not the cause as our last chat.

Can I suggest an etiquette way for this problem.
- I need that 'DCC>If file exists: Resume (Auto resume)' to auto-rename or auto-override for 'Invalid DCC ACCEPT' case,
instead of red print and do nothing (The DCC even persist and it must be manually canceled before download again).

How do you think about this solution?

FYI (so that you may found the cause), in those case 'IP' field will be port only display
e.g. ':6800' instead of xx.xx.xx.xx:6800 which will display normally as 'xx.xx.xx.xx:6800' after remove/rename that file and re-download (or overwrite it)

*:6800

FYI2, try in mIRC it can resume those file (from adi) so we can cut down the cause about file itself. It even report 100% for already complete file (adi also print 'Invalid DCC ACCEPT'). Maybe you forget to do something (e.g. set IP) in some conditional branch of resume?

That's not a solution, that's a work around, the original bug needs to be found and fixed.

You can try keep File -> Rawlog open at all times, when the problem happens next time, check the Rawlog Debug for any dcc related messages, also search through the network tab for the filename with the problem and copy all matches, then either paste it all here or if you are worried about privacy, email it to me on amundsen@gmail.com.

Also try think about the series of events that lead up to this issue, as much information as possible, e.g was the transfer manually cancelled, did the person in the other end cancel, did you cancel, did the user change nick.

Yeah, I thought so too but we still not found the cause root yet so little workaround seem nice at this moment. Sorry to ask for it but I need to quickly migrate myself from mIRC :P that's all the reason and workaround often faster than founding the root-cause.

*Note I add FYI2 in above comment when I try to find a root-cause

Log send.. (email)

It's clean and not miss any line because I do nothing else while testing - those are all logs.