PiwiklFatal error: Class 'Piwik_Session' not found in /.../.../.../index.php on line 0

Hi Guys,

I had installed Piwik and when i run the start parge i have that error. Can anyone help ?

Fatal error: Class ‘Piwik_Session’ not found in /…/…/…/index.php on line 0

Thx in advance

By “installed”, do you mean “unzipped” only, or did you go through the GUI installation steps?

hi, i did not instll it … another guy did it … i asked him now … and he sait that it worked just fine … untill he made an update … after that he had that error …

I encountered the same problem. Hope some can help. Thanks a lot!

hi guys … any ideea ? how can we solve that problem ? :smiley:

Issue still appearing many months after…

I have:

Fatal error: Class 'Piwik_Session' not found in /.../.../.../index.php [b]on line 62[/b]

This is following upgrade procedure to version 1.1.1, right after pasting/replacing all files, recuperating the config and accessing the index page.

And line 62 doesn’t even exist!!!

I am told that version 1.1 is a security upgrade but upgrade fails.

Any idea?

Did you manually update? The Piwik_Session class is found in core/Session.php.



I unzipped and uploaded the latest.zip download from a few hours ago.

I don’t know why it is not working. Re-did the manual upgrade procedure with same results.

It seems I cannot upgrade.

Any pointers?

Can you check your phpinfo? if you have eaccelerator, you have to disable it. it doesn’t work with the autoloader. eaccelerator users were getting errors with zend_registry but I’m guessing it’s erroring on Zend_Session (which Piwik_Session subclasses).

Thanks for the answer.

I confirm there are no eaccelerator installed. Some of my websites, not this one, have compression enabled so html is zipped before being sent to the visitor.

Other then that, I am using LAMP all in their latest versions available (not bleeding edge, stable releases).

Any other ideas?

Best regards.


I have the same problem. I hope what I found here will help me.


I confirm that zlib is not active on this domain and that no other form of eaccelerator are installed on the server.

I am still stuck!

Anything else you suggest I check?



Can you PM your phpinfo? It looks like there’s something atypical about your runtime environment.