Question

I did a simple pip install psycopg2 on mac system. It installed fine, but when I try to use psycopg2 I get the error:

Reason: Incompatible library version: _psycopg.so requires version 1.0.0 or later, but libssl.0.9.8.dylib provides version 0.9.8

pip freeze shows psycopg2==2.4.5 just right. I have installed psycopg2 on several virtualenvs but this is the first time I am seeing such error. I tried uninstalling and reinstalling, same results. Please help

Answer 1

I ran into a similar problem after upgrading to Mountain Lion.

Instead of copying libssl.* files per Slack’s suggestion, make sure that /usr/lib/libssl.dylib is actually a soft link to the most up-to-date version of the library.

E.g., on my machine, ls -l /usr/lib/libssl* gives:

lrwxr-xr-x  1 root  wheel    46B Jun 27 15:24 /usr/lib/libssl.1.0.0.dylib -> /Library/PostgreSQL/9.1/lib/libssl.1.0.0.dylib
lrwxr-xr-x  1 root  wheel    27B Jul 30 10:31 /usr/lib/libssl.dylib -> /usr/lib/libssl.1.0.0.dylib

If libssl.dylib doesn’t link to the version that the error version mentions, make sure you have that version of the library, and then make sure /usr/lib/libssl.dylib points to it, and not an older version.

If the link doesn’t exist, create it like so

sudo ln -s library_to_link_to link_to_create

using, of course, the proper locations for your machine. For me, this turned out to be:

sudo ln -s /usr/lib/libssl.1.0.0.dylib /usr/lib/libssl.dylib

Edit:

It seems like some are having trouble with part of my solution. Namely, deleting these important libraries even temporarily causes problems with the operating system.

Per Purrell’s answer, make sure you include the -fs flags when you use the ln command, which helps ensure that the libraries don’t go missing for a short period of time. E.g.,

sudo ln -fs /usr/lib/libssl.1.0.0.dylib /usr/lib/libssl.dylib
sudo ln -fs /usr/lib/libcrypto.1.0.0.dylib /usr/lib/libcrypto.dylib