Spyder: I can not open spyder 2.7. ValueError: Dependency has already been registered: pandas

Description of your problem

It seems that there are some conflicts with pandas. If I uninstall pandas, it works again. However, I need pandas.
Here is the log:
Traceback (most recent call last):
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\spyder.py", line 2367, in main
mainwindow = run_spyder(app, options, args)
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\spyder.py", line 2255, in run_spyder
main.setup()
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\spyder.py", line 779, in setup
from spyderlib.plugins.console import Console
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\plugins\console.py", line 30, in
from spyderlib.utils.environ import EnvDialog
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\utils\environ.py", line 17, in
from spyderlib.widgets.dicteditor import DictEditor
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\widgets\dicteditor.py", line 39, in
from spyderlib.widgets.dicteditorutils import (sort_against, get_size,
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\widgets\dicteditorutils.py", line 61, in
required_version=PANDAS_REQVER)
File "C:\Users\toluo\AppData\Local\Continuum\Anaconda\lib\site-packages\spyderlib\dependencies.py", line 68, in add
% modname)
ValueError: Dependency has already been registered: pandas
What steps will reproduce the problem?

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What is the expected output? What do you see instead?

Please provide any additional information below

Versions and main components

• Spyder Version:
• Python Version:2.7.13
• Qt Version:
• PyQt Version:
• Operating system:

Dependencies

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Help > Dependencies), press the button Copy to clipboard
and paste the contents below: