There is this neat little thing called VERSION NUMBER. How about you check it before asking us to reinstall a 20GB game just to see if it patched or not?
My file version (1.0.28.42246) hasn't changed, but I do wonder about all the hot fixes GBX has been putting out, and how that could affect us.
As a result, I'm sticking with the Editor and running in offline mode as much as possible.
I had to run the check integrity on my steam game and afterwards it started working fine again with the trainer. Not sure if this will help anyone or not. Also not to seem like a total dumb *ss but where do I look to see what version of the game I am running? I have tried everything and cannot find that.
Your Borderlands2 Application file version (Borderlands2.exe) needs to be the same as the Trainer version, as you probably know.
For me, that file is located at:
C:\Program Files (x86)\Steam\steamapps\common\Borderlands 2\Binaries\Win32\Borderlands2
That last Borderlands2 is the .exe file. You can hover your mouse over it, or right click it and then click properties, in order to see the file version (which is different from the product version, by the way).