TestFight beta testing for internal testers - Build state is "processing"
Normally you should never see the status 'Processing'. Once the build status is set to Processing, it will never be changed; at least in my case. (See image below)
The solution is to "keep trying." Try either increasing build number or version number, and keep submit to the iTunes Connect.
I got it work in the third attempt with no processing time.
Ok, here's the answer for the March 2015 people. I uploaded a pre-release build yesterday (4th March) via Xcode and the Internal & External Testing statuses are still at 'Processing' more than 36 hours later. I even tried re-uploading, increasing build numbers etc. No joy. So I called Apple. This is what they told me;
They have been seeing this problem happening regularly for those who have uploaded pre-release builds on the 4th and 5th of March. They've been investigating whether it's related to uploading via Xcode as opposed to via Application Loader, however they've been seeing the problem happening equally between both methods.
So they're looking into it & will be trying to solve the problem for my particular case asap.
I think with those who are finding that re-uploading with an increased build number is doing the trick, it's actually a red herring and is perhaps more to do with having re-submitted at a good moment for the system.
I'll keep this thread posted as to how it plays out. In the meantime, if your pre-release has been processing for more than 24 hours and you don't fancy the idea of littering your app's management console with pre-release upload attempts (that can't be deleted), I suggest giving Apple a call to get your upload kicked into action.
iTunes Connect Upload Helpline:
Inside US: +1 (800) 633-2152 From Outside: +1 (408) 974-4897
UPDATE 6th March: So, my original build finally came out of Processing. This took exactly 38 hours! I don't think this was Apple fixing it, it looks to me that this was it finally sorting itself out.
Before this I also tried uploading new incremented builds via Application Loader instead and also while logged-out of iTunes Connect, as per some of the suggestions below, but this didn't make a damned bit of difference for me. Which brings me to the fairly certain conclusion that it just works because you're submitting at a good moment (or perhaps may even be related your geographical location (I'm London)) and no other hokus pokus!
The original Testflight rather rudely puts Apple to shame here. They really need to sort this out.
It turned out that "Processing" a build, even if it is for internal testing only (i.e. the 25 accounts associated with your team) may take a couple of hours. Even if the binary has already been validated by Xcode and Application loader.
I'm posting this as an answer since I've found no evidence about how long the "Processing" state is supposed to be. Given the length of some of the reviewing process it could be seconds, minutes, hours or days so it's nice to know that in this case it lasted a couple of hours.
Now my console status is this one.