Our server kept crashing with http error 503 when going to a specific template that we were working on. The Kentico log had no error in it, but in the windows log this was shown:

Faulting application name: w3wp.exe, version: 7.5.7601.17514, time stamp: 0x4ce7afa2
Faulting module name: clr.dll, version: 4.0.30319.1, time stamp: 0x4ba21eeb
Exception code: 0xc00000fd
Fault offset: 0x00000000000d6331
Faulting process id: 0xb7c
Faulting application start time: 0x01cbde8388cd630e
Faulting application path: c:\windows\system32\inetsrv\w3wp.exe
Faulting module path: C:\Windows\Microsoft.NET\Framework64\v4.0.30319\clr.dll
Report Id: c8347f6a-4a76-11e0-b168-001dd8b71fc8

We were able to track it down to a webpart that was added to a webpart that had a macro: %Text% - not sure why this crashed Kentico, but once that web part was removed everything went back to normal.