.NET CLR crashes applications after 1+ year in service on Windows 8.1 Pro

Hi,

After 1+ year we suddenly see that .NET based apps crashed on Windows 8.1 Pro.
The PC has NOT been updated for the past year and no new applications installed.

Both our custom .NET based Windows server and SSMS crashes with an access violation in clr.dll?

Below from Windows Event Viewer.

SSMS

Faulting application name: Ssms.exe, version: 2011.110.5058.0, time stamp: 0x537406e3
Faulting module name: clr.dll, version: 4.0.30319.34014, time stamp: 0x52e0b784
Exception code: 0xc0000005
Fault offset: 0x00100d7a
Faulting process id: 0xb74
Faulting application start time: 0x01d12b6ac3f1f26b
Faulting application path: C:\Program Files (x86)\Microsoft SQL Server\110\Tools\Binn\ManagementStudio\Ssms.exe
Faulting module path: C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Report Id: 030caa7e-975e-11e5-8285-3417eb975419
Faulting package full name: 
Faulting package-relative application ID: 

Custom Windows Service, .NET framework target = 4.5

Faulting application name: SC.DataTransfer.App.exe, version: 1.0.0.1119, time stamp: 0x54086f52
Faulting module name: clr.dll, version: 4.0.30319.34014, time stamp: 0x52e0b784
Exception code: 0xc0000005
Fault offset: 0x00100d7a
Faulting process id: 0xf0c
Faulting application start time: 0x01d12b6abc0d5cb0
Faulting application path: C:\Program Files\XXXX\SC DataTransfer App\SC.DataTransfer.App.exe
Faulting module path: C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Report Id: f9fcf647-975d-11e5-8285-3417eb975419
Faulting package full name: 
Faulting package-relative application ID: