Cannot open include file: 'leptonica/allheaders.h': No such file or directory

tesseract_ocr.cpp(626): fatal error C1083: Cannot open include file: 'leptonica/allheaders.h': No such file or directory

    error: command 'C:\\Program Files (x86)\\Microsoft Visual Studio 14.0\\VC\\BIN\\x86_amd64\\cl.exe' failed with exit status 2

"mspdb100.dll couldn't be found by cl.exe "
 

For all above error we should make sure to follow following steps based on your OS version as mentioned in given link 

pip is not recognized as an internal or external command

If you are getting following error while running pip command in 'cmd'

pip is not recognized as an internal or external command 

Change installation path of Python from default location,
C:\User\username\AppData\Local\Programs\Python\Python36

to

C:\Python36

using Custom installation of Python.


Post that make sure Adding Python and PythonPath to the Windows environment:

1. Open Explorer.
2. Right-click 'Computer' in the Navigation Tree Panel on the left.
3. Select 'Properties' at the bottom of the Context Menu.
4. Select 'Advanced system settings'
5. Click 'Environment Variables...' in the Advanced Tab

       Under 'System Variables':

       Add

      PY_HOME

     "C:\Python3.6\"   

      PYTHONPATH

      %PY_HOME%\Lib;%PY_HOME%\DLLs;%PY_HOME%\Lib\lib-tk;C:\another-library

       Append

       PATH      %PY_HOME%;%PY_HOME%\Scripts

In case if it still doesn't work then you can prefix 'pip' with following commands:

py -m pip install