I installed Catalina on my macbook pro mid 2014 , and since then the wifi is disabled.

I see a light grey wifi symbol saying in the pull down menu " wifi switched on " ,and when I open the network preferences it says however " wifi switched off " ??

Networking works normal when using a wired connection.

Looking in the system overview under network/wifi it does not show any wifi adapter (my other macbook shows here airport extreme with a mac adres )

When I run the hardware check is says "no errors"

I do think however it is not a hardware, but a software problem. When immediately after starting up I look into the network preferences in the wifi section it says : "from localizable strings" and then in the status box : <do not loc> . After a few seconds followed by the status "Switched off"

I tried going back to the orignal OS Mavericks to see if that solves the problem, but that won't install (hampers on finding an installation disk)

Anybody any ideas what might be the problem ?