Error could not find a version that satisfies the requirement pywin32 from versions none

I have installed python 3.5, and need to install pywin (pywin32)

however, pip cannot find it. Note, i have just PIP install’ed send2trash and gitpython successfully

 Could not find a version that satisfies the requirement pywin32 (from versions: )

A few possibly relevant data points:

• new install of python 3.5
• windows 7 x64
• python 2.7 was previously installed on the machine
• as mentioned, several other packages were installed fine via PIP
• running these commands from git-bash, which came from the git windows installer, installed some time ago.
  — I have gnu grep in my path, so i believe i selected the git installer option to put the whole mysys toolchain in my path

full —verbose output:

C:UsersUSER>pip install  pywin32    --proxy http://proxy.COMPANY.com:8080
Collecting pywin32
  Could not find a version that satisfies the requirement pywin32 (from versions: )
No matching distribution found for pywin32

C:UsersUSER>pip install  pywin32    --proxy http://proxy.COMPANY.com:8080 --verbose
Config variable 'Py_DEBUG' is unset, Python ABI tag may be incorrect
Config variable 'WITH_PYMALLOC' is unset, Python ABI tag may be incorrect
Collecting pywin32
  1 location(s) to search for versions of pywin32:
  * https://pypi.python.org/simple/pywin32/
  Getting page https://pypi.python.org/simple/pywin32/
  Looking up "https://pypi.python.org/simple/pywin32/" in the cache
  Current age based on date: 61
  Freshness lifetime from max-age: 600
  Freshness lifetime from request max-age: 600
  The response is "fresh", returning cached response
  600 > 61
  Analyzing links from page https://pypi.python.org/simple/pywin32/
  Could not find a version that satisfies the requirement pywin32 (from versions: )
Cleaning up...
No matching distribution found for pywin32
Exception information:
Traceback (most recent call last):
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipbasecommand.py", line 215, in main
    status = self.run(options, args)
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipcommandsinstall.py", line 324, in run
    requirement_set.prepare_files(finder)
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipreqreq_set.py", line 380, in prepare_files
    ignore_dependencies=self.ignore_dependencies))
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipreqreq_set.py", line 554, in _prepare_file
    require_hashes
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipreqreq_install.py", line 278, in populate_link
    self.link = finder.find_requirement(self, upgrade)
  File "c:usersUSERappdatalocalprogramspythonpython35libsite-packagespipindex.py", line 514, in find_requirement
    'No matching distribution found for %s' % req
pip.exceptions.DistributionNotFound: No matching distribution found for pywin32 

Comments

Sometimes you get an error when you’re trying to install a Python package
using pip. It looks like this:

Could not find a version that satisfies the requirement (from versions:)
No matching distribution found for

Some probable reasons for this error are:

1. PyPI server isn’t responding to your requests. It can happen either because
   the PyPI server is down or because it has blacklisted your IP address. This
   happened to me once when I was trying installing packages on a server.
   This can be fixed by using a proxy with pip. See the solution below.

2. You’re running an older pip (especially on Mac). This can be fixed by
   upgrading your pip.
   See this post on Stack Overflow.
   Thanks to Anupam Jain who pointed this in a comment.

3. The package you’re trying to install is not available for your Python version.

4. The package is not available for your operating system. This is a rare case
   and only happens when the package is not pure-Python, i.e. it’s been
   partially written in C or Cython. Such a package needs to be compiled for
   every operating system (Windows/Mac/Linux) and architecture (32-bit/64-bit).
   Suppose a package has only been compiled for Windows 64-bit, then you’ll get
   this error if you try to install it on Windows 32-bit, or any other
   OS.

5. The package is not present on PyPI server. In this case pip will not work. So
   you’ll have to download and install the package manually from Github or wherever
   it is available.

Solution¶

I had this issue because PyPI server had blacklisted the IP
of my hosting provider, the obvious solution was to make pip install via a proxy.

But to see if that’s also the case with you, you can test it like this:

$ curl https://pypi.org

The requestors Network has been blacklisted due to excessive request volume. 
If you are a hosting customer, please contact your hosting company's support. 
If you are the hosting company, please contact infrastructure-staff@python.org to resolve

If you see the message similar to above, that means your IP has also been
blacklisted by https://pypi.org.

If you don’t see this message then the reason for the pip error could be that you’re using
an older version. See this post on Stack Overflow
for a solution.

Anyways, this can be fixed by using a proxy with pip.

Supplying a proxy address to pip is easy:

$ pip install -r requirements.txt --proxy address:port

Above, address and port are IP address and port of the proxy.

To find proxies, just search Google for proxy list.

Other things that I tried¶

These are some other things that I tried to get rid of this issue.
Although they didn’t work for me, but they might work for you.

1. Changing DNS resolver of my server.
   This makes sense if your server’s DNS resolver can’t find PyPI servers.
2. Reconfiguring SSL, reinstalling CA certificates.
   This makes sense if you don’t have updated CA certificates which are used by
   PyPI servers.
3. Downloading packages using wget.
   This is an alternative way to install Python packages. Download them via wget
   and then install them using python setup.py install. In my case, the server was
   blacklisted by PyPI so I was getting a 403 Forbidden error.
4. Downloading packages using curl.
   Alternative to wget. In my case I didn’t get a 403 error but rather it just
   created invalid tarball files, instead of actually downloading them.
5. Downloading packages using git or hg.
   If your desired packages have git or hg repositories that you can clone, this
   is a good workaround.