Question: Below is the error message when I run "scons" to compiler in windows7:

```
-----------------------------------------------------------------------------------
'cl' is not recognized as an internal or external command,
operable program or batch file.
scons: *** [out\windows-x86-MD-unicode-vs2008-rel\obj-static\src\featuresets\ada                                      pters\im-history\AddToChatRoomHistoryVisitor.obj] Error 1
scons: building terminated because of errors.
-----------------------------------------------------------------------------------

```

I have added path to environment variables already, but still met this problem.

Below is the PATH info of environment variables:

```
--------------------------------------------------------------------------------------------
PATH=C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v
1.0\;C:\Program Files\CREDANT\Shield v7.1\;C:\Program Files (x86)\QuickTime\QTSystem\;C:\Program Fil
es\Microsoft SQL Server\110\Tools\Binn\;C:\Program Files\TortoiseSVN\bin;C:\Python27;C:\cygwin64\bin
;C:\Python27\scons-2.3.1;c:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn\;c:\Program File
s\Microsoft SQL Server\100\Tools\Binn\;c:\Program Files\Microsoft SQL Server\100\DTS\Binn\;C:\Progra
m Files (x86)\Microsoft Visual Studio 10.0\VC\bin;C:\Python27\Scripts;C:\Program Files (x86)\Microso
ft Visual Studio 10.0\VC\lib;C:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\include
--------------------------------------------------------------------------------------------

```

Answer: 
The location of the cl.exe executable is not in the system **PATH** environment variable.

In other words the cmd.exe command line processor has been asked to run the cl.exe executable but it can't find it. It is either not in the **PATH** or not installed.

> 
> I have added path to environment variables already, but still met this problem.
> 
> 
> 

To test this open a command prompt and type in:

*cl.exe -?*
I was having the same issue and found a better way to fix it from @bdbaddog answer to get the debug log from `set SCONS_MSCOMMON_DEBUG=%TEMP%\SCONS_MSVS_DEBUG.log` SCons seem to find the cl.exe

```
00073ms:MSCommon/vc.py:_check_cl_exists_in_vc_dir#588:checking for cl.exe at C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.26.28801\bin\Hostx64\x64\cl.exe: 
00073ms:MSCommon/vc.py:_check_cl_exists_in_vc_dir#590:found cl.exe!: 

```

And scons env `env['ENV']['PATH']` has the `cl.exe` path but it doesn't use it, So I just updated the session path using scons path like below and it worked

```py
os.environ['PATH'] = env['ENV']['PATH']

```