I too have a similar problem.
I downloaded and installed CK2 with every available DLC from Steam back in January or February, 2013. I played a few rounds, but then moved on to other things.
Now, months later, when I try to run CK2, the following happens :
1. The launcher screen comes up, but the "mods" and "dlcs" areas are blank. I have no mods, but I have all the dlcs you could get from Steam at the time I purchased it (gold package or something).
2. When I hit the "Start CKII" button, this happens :
A dialogue comes up which says : "Unhandled exception has occurred in your application. If you click continue, the application will ignore this error and attempt to continue. If you click Quit, the application will close immediately. The system cannot find the file specified."
The details button shows this :
See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.
************** Exception Text **************
System.ComponentModel.Win32Exception: The system cannot find the file specified
at System.Diagnostics.Process.StartWithCreateProcess(ProcessStartInfo startInfo)
at System.Diagnostics.Process.Start()
at launcher.LauncherForm.ButtonFunction(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
************** Loaded Assemblies **************
mscorlib
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5466 (Win7SP1GDR.050727-5400)
CodeBase: file:///C:/Windows/Microsoft.NET/Framework/v2.0.50727/mscorlib.dll
----------------------------------------
launcher
Assembly Version: 0.0.0.0
Win32 Version: 0.0.0.0
CodeBase: file:///C:/Program%20Files%20(x86)/Steam/steamapps/common/Crusader%20Kings%20II/CK2game.exe
----------------------------------------
System.Windows.Forms
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5468 (Win7SP1GDR.050727-5400)
CodeBase: file:///C:/windows/assembly/GAC_MSIL/System.Windows.Forms/2.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)
CodeBase: file:///C:/windows/assembly/GAC_MSIL/System/2.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Drawing
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5467 (Win7SP1GDR.050727-5400)
CodeBase: file:///C:/windows/assembly/GAC_MSIL/System.Drawing/2.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Configuration
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
CodeBase: file:///C:/windows/assembly/GAC_MSIL/System.Configuration/2.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
Assembly Version: 2.0.0.0
Win32 Version: 2.0.50727.5420 (Win7SP1.050727-5400)
CodeBase: file:///C:/windows/assembly/GAC_MSIL/System.Xml/2.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
************** JIT Debugging **************
To enable just-in-time (JIT) debugging, the .config file for this
application or computer (machine.config) must have the
jitDebugging value set in the system.windows.forms section.
The application must also be compiled with debugging
enabled.
For example:
<configuration>
<system.windows.forms jitDebugging="true" />
</configuration>
When JIT debugging is enabled, any unhandled exception
will be sent to the JIT debugger registered on the computer
rather than be handled by this dialog box.
====
Clicking Continue does nothing.
Cant understand why it worked before and now it doesn't. Cant understand why the Steam doesn't update the game, and not require me to be a tech expert. Cant understand why I would have to "re-install" anything, or "move the CK2 folder to xxxxx" = getting a little tired of having to move folders in and out of steam applications. (When can I delete them? How much space are they taking on my HDD?).