preface
There are various problems encountered during the use of TensorFlow. It is helpful to write them down for review and future learning
Problem description
When TensorFlow is installed in Anaconda, the following problem is encountered:

>>> import tensorflow
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "D:\Anaconda\envs\dl\lib\site-packages\tensorflow\__init__.py", line 24, in <module>
    from tensorflow.python import pywrap_tensorflow  # pylint: disable=unused-import
  File "D:\Anaconda\envs\dl\lib\site-packages\tensorflow\python\__init__.py", line 59, in <module>
    from tensorflow.core.framework.graph_pb2 import *
  File "D:\Anaconda\envs\dl\lib\site-packages\tensorflow\core\framework\graph_pb2.py", line 6, in <module>
    from google.protobuf import descriptor as _descriptor
  File "D:\Anaconda\envs\dl\lib\site-packages\google\protobuf\descriptor.py", line 47, in <module>
    from google.protobuf.pyext import _message
ImportError: DLL load failed: The specified program could not be found.

The solution
Protobuf was upgraded yesterday when Object-Detection was installed, so if you call back the version of Protobuf, you should be fine.

pip install protobuf==3.6.0