Error with plugin openmediavault-mysql

Error with plugin openmediavault-mysql

After installing the plugin openmediavault-mysql 1.0.16, I am unable to activate the plugin.
The following error code pops up:

Fehler #4000:
exception 'OMVException' with message 'Failed to execute command 'omv-mkconf mysql 2>&1': Unable to find any database files in /var/lib/mysql.
Unable to find any database files in /media/34fd0dde-93fe-427a-953f-xxx/mysql/.' in /usr/share/openmediavault/engined/module/mysql.inc:88
Stack trace:
#0 /usr/share/openmediavault/engined/rpc/config.inc(180): OMVModuleMySQL->applyConfig()
#1 [internal function]: OMVRpcServiceConfig->applyChanges(Array, Array)
#2 /usr/share/php/openmediavault/rpcservice.inc(125): call_user_func_array(Array, Array)
#3 /usr/share/php/openmediavault/rpcservice.inc(158): OMVRpcServiceAbstract->callMethod('applyChanges', Array, Array)
#4 /usr/share/openmediavault/engined/rpc/config.inc(224): OMVRpcServiceAbstract->callMethodBg('applyChanges', Array, Array)
#5 [internal function]: OMVRpcServiceConfig->applyChangesBg(Array, Array)
#6 /usr/share/php/openmediavault/rpcservice.inc(125): call_user_func_array(Array, Array)
#7 /usr/share/php/openmediavault/rpc.inc(79): OMVRpcServiceAbstract->callMethod('applyChangesBg', Array, Array)
#8 /usr/sbin/omv-engined(500): OMVRpc::exec('Config', 'applyChangesBg', Array, Array, 1)
#9 {main}

What can I do?
Thanks
erik

no answers.
In the meantime a full purge of mysql and a clean new install of the mysql-plugin helped me out. I do not know whether everything is correct, sticking with owncloud doesn't work.

Just the plugin or the whole OMV from scratch?

Purging (for beginners) always incorporates the danger to wipe the dependencies and to blame the system.
And even as it works, it has no learning effect.

So I prefer to test out new thinks in a VM, but sometimes ok in VM, anyway causing problems on bare metal.