Upgrading to the latest CiviCRM on a drupal based site didn't seem to be an issue. About a week later, perhaps a change in PHP version, I noticed that my entire site gives this message now and nothing really works: Fatal error: Class 'CRM_Extension_System' not found in .../public_html/sites/all/modules/civicrm/CRM/Core/PseudoConstant.php on line 1837

Any ideas as to what I may have done to cause this? Thank you for all your help!

Regards, Yasir

  • 1
    Please specify the versions of CiviCRM and of PHP before and after the updates.
    – choster
    Commented Dec 2, 2015 at 18:28
  • Did you find the cause of this? I'm having the same problem, something is modifying: CRM>Contact>Import>Field.php.suspected CRM>Contact>Page>Dashboard.php.suspected Extension > System.php.suspected Commented Dec 30, 2015 at 14:22
  • The same problem in our site. Hosting company told us that they don´t run any antivirus/antimalware. It is supposed to be done by 2 separate hacking attacks. Didn´t find any solution to this problem yet, so any help would be very welcome.
    – user2864
    Commented Feb 26, 2016 at 13:36
  • Sounds like an external hack, not to do with the upgrade process. Worrying stuff though. Was this a Drupal or a WordPress site? What versions, and what version of Civi?
    – JohnFF
    Commented Feb 26, 2016 at 23:06

4 Answers 4


I had the same issue and the same solution - the antivirus renamed the

httpdocs > sites > all > modules > civicrm > CRM > Extension > System.php.suspect

Not sure how to make the server leave that file alone, or what triggered it.

  • I had this same issue and was able to fix by renaming. So what exactly renamed this file to begin with? Commented Apr 19, 2016 at 17:13
  • You've been hacked. This is caused by a trojan or script injection. There will be several files affected. It will continue to re-infect until you fix permissions on your server files. Commented Apr 24, 2016 at 19:44

It looks like your upgrade process did not run smoothly could you check whether the file CRM/Extensions/System.php does exist? If not then it looks like not all source files are on the server.

ps. It is usually a good idea to have test environment where you could test upgrades before actually performing them on production. The same is true for upgrading to the latest php version. First do that in a test environment.

  • Thanks Jaap. The file was there, but it was renamed to System.php.suspected. Any ideas on how the file could have been renamed?
    – Yasir
    Commented Dec 8, 2015 at 0:22
  • 2
    Could this be done by any anti virus software? Commented Dec 8, 2015 at 6:51
  • I think that's the case Jaap. Thank you.
    – Yasir
    Commented Dec 10, 2015 at 3:58

I would try clear caches first to ensure everything is being picked up from the file system. From the error it looks as though a site move has taken place or the directories have moved/been renamed?


Check it after deleting the temporary folder of civicrm.

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