I am using win10, emacs version is GNU Emacs 26.3. python version is Python3.6.8. After install EIN (EIN version is 20190813.2156) package and try to run M-x ein:login, I got below error message:

ein: [error] Login to failed,
error-thrown (error . exited abnormally with code 2 ), 
raw-header curl: option --compressed: 
the installed libcurl version doesn't support this

    curl: try 'curl --help' for more information

Mark set [3 times]

How should I fix this curl issue?

  • On Running command ``` where curl C:\Windows\System32\curl.exe C:\cygwin64\bin\curl.exe ``` I am able to run curl command from cygwin drive but not able to run it from windows command prompt. C:\cygwin64\bin\curl.exe --version is giving the latest version. what i need to do to run it from windows command prompt.
    – shane123
    Commented Jan 21, 2020 at 14:45

2 Answers 2


I was able to bypass the issue (at least connects) by commenting the --compressed line in request.el ~/.emacs.d/elpa/.../request-20190923.1502/request.el

line 909 inside (cl-defun request--curl-command)

;; FIXME: test automatic decompression
;; "--compressed" ;; this line originally was not commented

Maybe the automatic decompression in windows was not tested? its strange because curl (from anaconda or cygwin) have the compressed flag

curl --help
Usage: curl [options...] <url>
     --abstract-unix-socket <path> Connect via abstract Unix domain socket
     --anyauth       Pick any authentication method
 -a, --append        Append to target file when uploading
     --basic         Use HTTP Basic Authentication
     --cacert <file> CA certificate to verify peer against
     --capath <dir>  CA directory to verify peer against
 -E, --cert <certificate[:password]> Client certificate file and password
     --cert-status   Verify the status of the server certificate
     --cert-type <type> Certificate file type (DER/PEM/ENG)
     --ciphers <list of ciphers> SSL ciphers to use
     --compressed    Request compressed response
     --compressed-ssh Enable SSH compression

I know it's a hack and not a solution, so use at your own discretion.


Check if you have curl package installed in python/conda library. I was getting the same error when starting jupyter notebook, where curl installation from win32 library was being picked up. Also make sure your PATH precedence picks up the correct curl installation.

To check for curl installation on Windows, start cmd prompt:

where curl

which returns all instances of curl (in order). Make sure Python/Conda install takes precedence.

  • Can you add instructions on how to check these things? Having a step by step guide would make this answer much clearer.
    – user12563
    Commented Sep 30, 2019 at 15:59

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