Unable to run application outside of Visual Studio

Our .Net 4.0 app that runs normally while hosted by VS always crashes while loading (less than 1 second after executing) while not debugging (both debug and release binaries).

The app contains 5 libraries (all of it with .Net 4.0) + NHibernate dependencies.

It does not even fire the UnhandledException event, it just crashes right away with a OutOfMemoryException (I could only see that with the Windows Event Viewer).

Event Viewer tells me that kernelbase.dll had a OutOfMemoryException, and Fuslogvw.exe tells me that System.Core fails to load:

*** Input Assembly Binder Log (6/27/2016 @ 15:41:54) ***
The operation failed.

Result of the Association: hr = 0x8007000e. Insufficient storage space to complete the operation.

Assembly Manager loaded from: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll

Running under executable C:\Users\User\Source\Manager\MySoftware\MySoftware.WPF.App\bin\Release\MySoftware.WPF.App.exe

---Follows a detailed log of errors.

=== Pre-Association state information ===

LOG: DisplayName = System.Core, Version = 4.0.0.0, Culture = neutral, PublicKeyToken = b77a5c561934e089
(Fully-specified)
LOG: Appbase = file:///C:/Users/User/Source/Manager/MySoftware/MySoftware.WPF.App/bin/Release/
LOG: initial PrivatePath = NULL
Logging: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = MySoftware.WPF.App.exe
Calling assembly: MySoftware.WPF. App, Version 1.0.0.0, Culture = neutral, PublicKeyToken = null.

===
LOG: this Association starts at the default load context.
LOG: using application configuration file: C:\Users\User\Source\Manager\MySoftware\MySoftware.WPF.App\bin\Release\MySoftware.WPF.App.exe.Config
LOG: using host configuration file:
LOG: using machine configuration file C:\Windows\Microsoft.NET\Framework64\v4.0.30319\config\machine.config.
LOG: post policy reference: System.Core, Version = 4.0.0.0, Culture = neutral, PublicKeyToken = b77a5c561934e089
LOG: assembly located by searching on GAC.

ERR: unrecoverable error during pre download verification (hr = 0x8007000e).

I have 4GB of RAM with 60% occupied, so maybe that's not the problem. Can you give me a hint where to look?