'Cache entry deserialization failed, entry ignored

C:\Users\deypr>pip3 install sklearn

Collecting sklearn

  Cache entry deserialization failed, entry ignored

  Retrying (Retry(total=4, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)': /simple/sklearn/

  Retrying (Retry(total=3, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)': /simple/sklearn/

  Retrying (Retry(total=2, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)': /simple/sklearn/

  Retrying (Retry(total=1, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)': /simple/sklearn/

  Retrying (Retry(total=0, connect=None, read=None, redirect=None, status=None)) after connection broken by 'SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)': /simple/sklearn/

  Could not fetch URL https://pypi.python.org/simple/sklearn/: There was a problem confirming the ssl certificate: HTTPSConnectionPool(host='pypi.python.org', port=443): Max retries exceeded with url: /simple/sklearn/ (Caused by SSLError(SSLError(1, '[SSL: TLSV1_ALERT_ACCESS_DENIED] tlsv1 alert access denied (_ssl.c:777)'),)) - skipping

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

I am getting this error whenever trying to install any python3 package.

What could be the possible reasons?
How to fix it ?

Solution 1:^[1]

It was a network issue. It worked totally fine when I moved to a different network.

Solution 2:^[2]

Regarding the error/warning message in the question's title:

Cache entry deserialization failed, entry ignored

You can fix it by removing the pip cache, e.g. on Ubuntu:

rm -rf ~/.cache/pip

Solution 3:^[3]

Its scikit-learn not sklearn on pypi. Check the documentation here

Try:

pip3 install scikit-learn

Solution 4:^[4]

Just run the pip command with --no-cache-dir.

For example:

>>> pip install keras --no-cache-dir

Solution 5:^[5]

Another reason might be that you have a lower python version. For instance, you install tensorflow on python 3.6.0 and you'll get Cache entry deserialization failed, entry ignored for many libraries that come with tensorflow.

But if you use python 3.8.0, all is good.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Muhammad Dyas Yaskur
Solution 2	Franck Dernoncourt
Solution 3	Vivek Kumar
Solution 4	B. Kanani
Solution 5	Bendemann

'Cache entry deserialization failed, entry ignored

Solution 1:[1]

Solution 2:[2]

Solution 3:[3]

Solution 4:[4]

Solution 5:[5]