Fatal error on activation

[photocurio]

Fatal error: Cannot declare class QM_Activation, because the name is already in use in /chassis/content/plugins/query-monitor/classes/Activation.php on line 0

When I try to network-activate this plugin I get the above error. The site is a multisite localhost install. I pulled the database from a different development environment that has Query Monitor active. After the usual search-and-replace actions everything works well except this plugin. Is there something in the database I can remove so I can activate Query Monitor on my new localhost?

[johnbillion]

Very odd. Not sure what would cause that.

• Have you checked the mu-plugins directory to ensure QM isn't in there?
• Is QM active on any sites individually? Try deactivating it on each site if so.
• Is wp-content/db.php in place? Try deleting it if so.
• Is the chassis/Query_Monitor extension present?
• Try flushing your cache with wp cache flush.
• Try flushing your opcode cache (restarting Chassis might do this).

[johnbillion]

Based on https://github.com/humanmade/Cavalcade/issues/96 it looks like you're running Altis. If so, you don't need to install Query Monitor separately as it's bundled with Altis.

Let me know if this isn't the problem and we can reopen this.

[photocurio]

@johnbillion yes, that explains it!

[rmccue]

(Specifically, it's provided by the altis/dev-tools Composer module.)

[eduwass]

In case this is useful for a future person trouble-shooting...

Today I was getting Fatal error: Cannot declare class ComposerAutoloaderInitd4d7d7d11152077b8234a5ecb185a7c0 on wp-content/plugins/query-monitor/vendor/composer/autoload_real.php after duplicating a site in LocalWP.

Was fixed after doing following steps mentioned on https://github.com/johnbillion/query-monitor/issues/509#issuecomment-609497689

• Have you checked the mu-plugins directory to ensure QM isn't in there?
• Is wp-content/db.php in place? Try deleting it if so
• Try flushing your cache with wp cache flush.