Microsoft .Net Framework - Unhandled Exception - File format is not valid

[PatchMyPCUpdaterM]

When I startup "Patch My PC Updater 4.1.0.4" (so the latest), I get the following error message:

Microsoft .Net Framework - Unhandled Exception - File format is not valid

My PC:

OS: Windows 10 Pro - 64 bit
Version: 10.0.18363 Build 18363

Reinstalling and rebooting .Net Framework 3.5 (inludes 2.0 and 3.0) does not solve the problem.

How to solve this issue ?

Thanks in advance.

***
Details:

See the end of this message for details on invoking
just-in-time (JIT) debugging instead of this dialog box.

************** Exception Text **************
System.ArgumentException: File format is not valid.
   at System.Windows.Forms.RichTextBox.StreamIn(Stream data, Int32 flags)
   at System.Windows.Forms.RichTextBox.StreamIn(String str, Int32 flags)
   at System.Windows.Forms.RichTextBox.set_Rtf(String value)
   at System.Windows.Forms.RichTextBox.OnHandleCreated(EventArgs e)
   at System.Windows.Forms.Control.WmCreate(Message& m)
   at System.Windows.Forms.Control.WndProc(Message& m)
   at System.Windows.Forms.RichTextBox.WndProc(Message& m)
   at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)


************** Loaded Assemblies **************
mscorlib
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4180.0 built by: NET48REL1LAST_B
    CodeBase: file:///C:/Windows/Microsoft.NET/Framework64/v4.0.30319/mscorlib.dll
----------------------------------------
PatchMyPC
    Assembly Version: 4.1.0.4
    Win32 Version: 4.1.0.4
    CodeBase: file:///C:/PatchMyPC.exe
----------------------------------------
Microsoft.VisualBasic
    Assembly Version: 10.0.0.0
    Win32 Version: 14.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.VisualBasic/v4.0_10.0.0.0__b03f5f7f11d50a3a/Microsoft.VisualBasic.dll
----------------------------------------
System
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4001.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System/v4.0_4.0.0.0__b77a5c561934e089/System.dll
----------------------------------------
System.Core
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4180.0 built by: NET48REL1LAST_B
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Core/v4.0_4.0.0.0__b77a5c561934e089/System.Core.dll
----------------------------------------
System.Windows.Forms
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.4150.0 built by: NET48REL1LAST_C
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Windows.Forms/v4.0_4.0.0.0__b77a5c561934e089/System.Windows.Forms.dll
----------------------------------------
System.Drawing
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Drawing/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Drawing.dll
----------------------------------------
System.Configuration
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Configuration/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Configuration.dll
----------------------------------------
System.Xml
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Xml/v4.0_4.0.0.0__b77a5c561934e089/System.Xml.dll
----------------------------------------
System.Runtime.Remoting
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Runtime.Remoting/v4.0_4.0.0.0__b77a5c561934e089/System.Runtime.Remoting.dll
----------------------------------------
System.Management
    Assembly Version: 4.0.0.0
    Win32 Version: 4.8.3752.0 built by: NET48REL1
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/System.Management/v4.0_4.0.0.0__b03f5f7f11d50a3a/System.Management.dll
----------------------------------------
Microsoft.Win32.TaskScheduler
    Assembly Version: 2.5.28.0
    Win32 Version: 2.5.28.0
    CodeBase: file:///C:/WINDOWS/Microsoft.Net/assembly/GAC_MSIL/Microsoft.Win32.TaskScheduler/v4.0_2.5.28.0__0d013ddd5178a2ae/Microsoft.Win32.TaskScheduler.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.

***