Python 3.5 crashes on wrong %PYTHONHOME

[Gisle Vanem]

I just installed the 32-bit Python 3.5b4 via the Web-installer.
First, I was a bit annoyed by the fact it installed under
   'f:\ProgramFiler-x86\Python35' instead of
   'f:\ProgramFiler\Python35' as I customided for. But I guess
this is a WOW64 thing. I'm on Win-8.1 (64-bit).

But then I noticed the whole thing crashes when calling
python35!Py_FatalError. On a simple 'python -v' command.

Presumably because my env-var:
  PYTHONHOME=f:\Programfiler\Python27

(and not 'PYTHONHOME=f:\Programfiler\Python35').

Reading the message on this list, gave me the impression
Python 2.7 and Python 3.5 can co-exist with no problem.
Doesn't look the case so far. Is there another 'PYTHONxx'
env-var to override 'PYTHONHOME' in this case? Or what should
I do to keep on using both 27 and 35?

For reference, the call-stack:

   ucrtbase!abort+0x4b
   python35!Py_FatalError+0xbc
   python35!Py_InitializeEx_Private+0x45b
   python35!Py_Main+0x72c
   python+0x11df
   KERNEL32!BaseThreadInitThunk+0x24
   ntdll!__RtlUserThreadStart+0x2f
   ntdll!_RtlUserThreadStart+0x1b

And some of the modules shown in WinDbg:

   ModLoad: 1c470000 1c47c000   F:\ProgramFiler\Python35\python.exe
   ModLoad: 77720000 7788e000   C:\Windows\SYSTEM32\ntdll.dll
   ModLoad: 77500000 77640000   C:\Windows\SYSTEM32\KERNEL32.DLL
   ModLoad: 76e20000 76ef7000   C:\Windows\SYSTEM32\KERNELBASE.dll
   ModLoad: 6cd50000 6d057000   F:\ProgramFiler\Python35\python35.dll
   ModLoad: 6e7e0000 6e7f5000   C:\Windows\SYSTEM32\VCRUNTIME140.dll

(the new universal CRT from MS)


-- 
--gv