truncate at 255 characters with xlsx files（OLEDB方式读取Excel丢失数据、字符串截断的原因和解决方法）

The TypeGuessRows setting is supported by ACE. Note the version numbers in the key may change depending upon the version of Office installed.

For 32-bit Windows (32-bit Office):
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Office\12.0\Access Connectivity Engine\Engines\Excel

For 64-bit Windows (32-bit Office):

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Office\12.0\Access Connectivity Engine\Engines\Excel

 Change TypeGuessRows  to 0.