Hello,
I'm looking at the issue right now, I don't not sure why this is happening, but you may try these two options:

• re-install Microsoft .NET Framework 4.5.2: https://www.microsoft.com/en-us/download/details.aspx?id=42643
• delete a file "C:\Program Files (x86)\Steam\steamapps\common\Arma 3\arma3launcher.exe" and a folder "C:\Program Files (x86)\Steam\steamapps\common\Arma 3\Launcher" and run verify the game cache again.

I reinstalled .NET Framework 4.5.2. I then deleted arma3launcher.exe and the Launcher folder.

33 files were reacquired after verification of game cache. Returns same error.
New .txt named:

"After Fix Attempt Arma3Launcher_Exception_20150719T150716.txt"

Could you please download a special version Launcher, extract it to the desktop and run it from there? It's basically same as the one you have, but that error report contains more information.

Download link: http://arma.jiripolasek.com/Files/Launcher_131546.zip

Sorry for the delay in reply; I forgot that I was going away.

I have extracted the file to the desktop (The file both directly on the desktop and in the folder it arrived in.)

Running the program normally / as admin seems to be doing anything. Nothing opens, my Steam doesn't switch to "In-Game Arma 3", and a error report is not created.

Could you please check that there is no running process arma3launcher.exe in Task Manager?

Also if you open Event Viewer and go to Windows Logs / Application, is there any error from the time you ran Launcher?

I have two errors appear when I launch the linked launcher. I have linked copy + pastes of the errors from the Steam Launcher and the link Launcher below.

http://pastebin.com/srfsEMWp

A friend of mine has looked over the error logs and believes it's something Visual C++ 2010 related. I believe these problems started AFTER attempting to install PlayWith6. I have tried reinstalling Visual C++ 2010 but as I have newer versions installed, it won't allow me to install it.
PlayWith6 also fails to load and doesn't install correctly.

Hello,
a description from the error pretty much summarize it: "The process was terminated due to an internal error in the .NET Runtime".

So far I was able to match the error with this article on Microsoft Knowledge Base: https://support.microsoft.com/en-us/kb/2640103 but I believe that their hotfix won't be applicable to you as you should already have a never version of those files. I'll keep looking for other possible solutions.

I can think of one more option. Microsoft has released .NET Framework 4.6 this Monday, you may want to try it: http://www.microsoft.com/en-us/download/details.aspx?id=48130

The .NET update has fixed it. Thanks a lot!
I think my PC's updating isn't set up right so I'll fix that!

Thanks again!

--Issue Resolved--

I'm glad to hear that it's fixed for you.