GLIBCXX_3.4.20 not found, how to fix this error?

I had the same issue while installing Ubuntu 18.04 in Virtualbox with the live-server image. I'm not sure what I did wrong but got the same error

"apt-get: symbol lookup error: /usr/lib/x86_64-linux-gnu/libstdc++.so.6: undefined symbol: , version GLIBCXX_3.4.11"

I was using 64-bit and had to download this file by using

wget http://security.ubuntu.com/ubuntu/pool/main/g/gcc-8/libstdc++6_8.4.0-1ubuntu1~18.04_amd64.deb

and installed using dpkg -i. Then everything runs normal with APT.

Then did an apt-get upgrade to make sure all is well.

Before installing:

This workaround is required to avoid libstdc++ errors while running "extended" hugo with SASS support.

wget -q -O libstdc++6 http://security.ubuntu.com/ubuntu/pool/main/g/gcc-5/libstdc++6_5.4.0-6ubuntu1~16.04.10_amd64.deb
sudo dpkg --force-all -i libstdc++6

Installation:

wget -q -O hugo.deb https://github.com/gohugoio/hugo/releases/download/v0.46/hugo_extended_0.46_Linux_64bit.deb
sudo dpkg -i hugo.deb

I found this solution here on the Hugo support forum

I solved problem like this (but GLIBCXX_3.4.21) on CentOS but it is not dependent from os. The library is part of gcc compiler so need to install or compile appropriate version of gcc. This is table of versions of gcc and versions of appropriate libstdc++:

GCC 4.9.0: libstdc++.so.6.0.20
GCC 5.1.0: libstdc++.so.6.0.21
GCC 6.1.0: libstdc++.so.6.0.22
GCC 7.1.0: libstdc++.so.6.0.23
GCC 7.2.0: libstdc++.so.6.0.24
GCC 8.0.0: libstdc++.so.6.0.25

( full list of versions is here )

It is not dependent from how to install gcc - it may be installed from package or compiled and installed from sources.

It is possible that system gcc libraries is available instead of newely installed. So need to specify environment variable where to find libraries for example in command line like this:

$ LD_LIBRARY_PATH=/usr/local/lib64 command args ...

I've had that numerous times through out the years with many different packages. It has always been resolved by:

sudo apt-get dist-upgrade

If your dist is upgradable, it will almost always bring down a new C++ library and reconfig things such as that they work again. The issue is almost always caused by your system not pointing to the right library. In my case, usually caused by pointing to a cross-compiler version of a library.

It happened to me with anaconda 4.0.0 (as @mjp stated), but the fix for me was to run this command in my environment:

conda install libgcc

I had this issue - it was because Anaconda2 didn't have the GLIBCXX_3.4.20 version of whatever that thing is. Only up to .19, the same as yours.

However, Ubuntu's library did have it. So I just created a softlink/shortcut in the Anaconda library to the actual Linux library containing that GLIBCXX_3.4.20, replacing the previous one, and it worked fine after restarting the python GUI (Spyder).

There should be a folder called libstdc++.so.6 in the Anaconda library, which is here: ~/anaconda2/lib. Within this folder is the versions of the script/library-code-thing, excluding the one that you're missing: GLIBCXX_3.4.20

Follow these steps to solve the issue:

1. go to the right location and backup your current anaconda2 shortcut (change its name so it isn't overwritten):

   cd ~/anaconda2/lib
   mv -vf libstdc++.so.6 libstdc++.so.6.old
   

2. create a new shortcut using the ln command (I am assuming that I am in the previous location ~/anaconda2/lib):

   ln -s /usr/lib/x86_64-linux-gnu/libstdc++.so.6 ./libstdc++.so.6
   

3. restart spyder / other interface you use

It should now work!

sudo cp /usr/bin/YourGccVersionLibrary/lib64/libstdc++.so.6 /usr/bin/YourGccVersionLibrary/lib64/libstdc++.so.6.0.20 /usr/lib/x86_64_linux-gnu/

I was having the same problem when trying to run other program, and found a solution on StackOverflow.

Basically, just do the following commands: Firstly, install:

sudo apt-get install libstdc++6

This should already be installed by default, but try it anyway. If it doesn't solve it, just do the following:

sudo add-apt-repository ppa:ubuntu-toolchain-r/test 
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade

I didn't perform the "dist-upgrade" command, but the ones before solved it for me