You need to uninstall both, since mods like CORE are not supported.
Install vanilla versios and then patch DD with 1.2 and HOI2 with latest pach.
Install vanilla versios and then patch DD with 1.2 and HOI2 with latest pach.
I do not see anything in there about patching to 1.1Castellon said:Don't install CORE.
Patch DD to 1.2 then install and patch HOI2.
Then when it all works, you can install user mods.