Cmc.log is full of Errors: Error creating RRD for pnp_multiple... but this RRD exists

[andreas-doehler (Andreas)]

@Vyda

Afterwards I still have a folder per monitored host in my “~/var/pnp4nagios/perfdata/” folder and ~/var/check_mk/rrd/ is empty.

Then you forgot to create the RRD rules inside your configuration.
Please first create two rules with “Configuration of RRD databases of services/hosts” and then do the convert again.