diff --git a/freqtrade/data/history/jsondatahandler.py b/freqtrade/data/history/jsondatahandler.py
index ee653d937..2b738a94a 100644
--- a/freqtrade/data/history/jsondatahandler.py
+++ b/freqtrade/data/history/jsondatahandler.py
@@ -71,8 +71,7 @@ class JsonDataHandler(IDataHandler):
             return DataFrame(columns=self._columns)
         pairdata = read_json(filename, orient='values')
         pairdata.columns = self._columns
-        pairdata = pairdata.astype(copy=False,
-                                   dtype={'open': 'float', 'high': 'float',
+        pairdata = pairdata.astype(dtype={'open': 'float', 'high': 'float',
                                           'low': 'float', 'close': 'float', 'volume': 'float'})
         pairdata['date'] = to_datetime(pairdata['date'],
                                        unit='ms',