Python randomly failing with no error

[FrankOgiamien]

I have a Win7 64bit machine and recently upgraded from 10.1 to 10.3   A script that used to work fine now finishes incomplete without tripping any error messages.   How would I troubleshoot this?

I added "try: except Exception as e: " logic but it does nothing. 

On the latest attempt, the last print statement to show up in my shell was for line 122 of the 573 line script.   Then it ended with the usual shell prompt like below.

================= RESTART ============

>>>

[DanPatterson_Retired]

python version etc? 

is this an absolutely clean install of Arc* and python etc? or a patched/upgraded version?

Did python ever work? was it used before ArcMap 10.3 was installed etc?  The details will help

[FrankOgiamien]

Hi Dan, I was using py 2.7.2 with Arc 10.1  recently went through all the steps to upgrade to Arc 10.3.  Ran installs for: - ArcGIS_Desktop_103_141985.exe

     - Python_278_64bit_144162.exe

     - ArcGIS_BackgroundGP_for_Desktop_103_141996.exe

I don't remember if I ran the install for Python32bit, maybe that's the problem. and I don't recall the order of the installs for the last 2.

The process did an uninstall of 10.1 however I don't know how clean that is.

Found a few patches for 10.3 yesterday on ESRI's site and installed those with no luck.

10.1 and py2.7.2 was solid for me.  If there's no known bugs I may have to try a uninstall/reinstall, or go back down to 10.1    First I'll test my project on an older 10.1 machine.

Thanks