Stop edge crashing when opening PDFs

Edge browser closes immediately when trying to open a PDF file. More of a problem after MS Reader was withdrawn!

From https://community.ivanti.com/thread/60187:

  1. Go to HKCU\Software\Microsoft\Internet Explorer\

  2. Create a new (sub-)key called “Spartan” and enter it. You should now be in HKCU\Software\Microsoft\Internet Explorer\Spartan\

  3. Add a DWORD called RAC_LaunchFlags and give it a value of 1