Traceback (most recent call last):
File "D:\GitHub\vnpy\vnpy\trader\ui\mainwindow.py", line 282, in open_widget
widget = widget_class(self.main_engine, self.event_engine)
File "D:\ProgramData\Anaconda3\envs\python37\lib\site-packages\vnpy_ctastrategy\ui\widget.py", line 38, in init
self.cta_engine.init_engine()
File "D:\ProgramData\Anaconda3\envs\python37\lib\site-packages\vnpy_ctastrategy\engine.py", line 115, in init_engine
self.load_strategy_data()
File "D:\ProgramData\Anaconda3\envs\python37\lib\site-packages\vnpy_ctastrategy\engine.py", line 834, in load_strategy_data
self.strategy_data = load_json(self.data_filename)
File "D:\GitHub\vnpy\vnpy\trader\utility.py", line 99, in load_json
data = json.load(f)
File "D:\ProgramData\Anaconda3\envs\python37\lib\json__init.py", line 296, in load
parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
File "D:\ProgramData\Anaconda3\envs\python37\lib\json\init__.py", line 348, in loads
return _default_decoder.decode(s)
File "D:\ProgramData\Anaconda3\envs\python37\lib\json\decoder.py", line 337, in decode
obj, end = self.raw_decode(s, idx=_w(s, 0).end())
File "D:\ProgramData\Anaconda3\envs\python37\lib\json\decoder.py", line 355, in raw_decode
raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 30 column 21 (char 682)

请删除C:\users\administrator.vntrader文件夹里对应的json文件：cta_strategy_data.json
注意，这里的administrator应该是你的Windows操作系统用户名。删除后重启VN Trader即可。

如果后续再次出现该错误，请检查策略代码中，是否有把str、bool、int、float类型以外的变量名称写到了parameters列表中，这四种类型以外的变量由于无法通过json序列化会导致保存策略状态出错（损坏json文件）。

万分感谢，已解决。