Lost path info upon updating PYTHONPATH from Spyder

If relevant, please answer to the following questions:
1. What version of Python(x,y) have you installed?
2.7.2.3
2. Which components have you installed (Python(x,y) installer:
componentpage):
    b. Have you selected the "Full" component selection?

3. Have you selected the option "Customize installation directories"?
b. No

4. If the answer to 3. is yes, what installation directories have you
chosen?

5. Where did you install Python(x,y) itself?
a. default path

6. Have you installed Python(x,y):
    a. For "Current user only"

7. What is your operating system?
c. Windows 7

8. Is the operating system 64 bit?
a. Yes

9. When you installed Python(x,y), were you logged in as :
a. a regular user

10. If you are using Windows Vista/7, have you installed Python(x,y):
    b. by right-clicking on the installer and selecting "Run as an
administrator"

11. Regarding installed software on your machine, how did you clean your
machine before installing Python(x,y)  (multiple answers are possible):
a. you didn't do anything, you installed Python(x,y) directly on your
machine without precaution

What steps will reproduce the problem?
1. Go to Spyder
2. Go to PYTHONPATH management
3. Add some extra folders
4. Push the Syncronize button

What is the expected output? What do you see instead?
1. Python x,y does not start
2. Spyder does not start

Please provide any additional information below.

Original issue reported on code.google.com by marin...@gmail.com on 1 May 2013 at 6:33

clonly / pythonxy

Lost path info upon updating PYTHONPATH from Spyder #651