Fatal error: Cannot redeclare class Piwik\Plugin\Manager

Support & Bugs
1

Hello, I recently updated our Piwik installation from 2.12.0-r2 to 2.15.0, about five days ago.

Today we ran into an issue where the dashboard widgets were all showing this error:

Fatal error: Cannot redeclare class Piwik\Plugin\Manager in C:\inetpub\oursite\core\Plugin\Manager.php on line 39

I Restarted the IIS server and that seemed to have made the error go away and things are back to normal, but I expect it may happen again. Do anyone have insight into what might have caused this? Any assistance is greatly appreciated, thank you.

Server information:
Windows Server 2008 R2 (IIS 7.5)
Piwik 2.15.0 (upgraded from 2.12.0-r2)
PHP 5.6.0
MySQL Server 5.6

2

After upgrading Piwik, it may be useful to restart the server on IIS to clear some caches. This error should not occur again.