Q: My macbook pro mid2010 has a problem with WiFi after El Capitán 10.11.6 Update

Hello Carmenvima, 

Thanks for using Apple Support Communities.

I see that after you've updated your MacBook, it is having trouble connecting to Wi-Fi networks and is giving you a 'Wi-Fi: No hardware installed' message. I use Wi-Fi all the time on my MacBook, so know how important it is we get this resolved. I have a couple of things that I would like you to try.

First, reset the System Management Controller (SMC). The SMC is a part inside of your Mac that is in charge of controlling a lot of your Mac's hardware. The article below tells you how to reset it. After it's been reset, test out your Wi-Fi.

Reset the System Management Controller (SMC) on your Mac 

If you're still having problems locating your Wi-Fi router and connecting, try to start your MacBook into safe mode and see if you get the same Wi-Fi no hardware installed message. Safe mode (sometimes called safe boot) is a way to start up your Mac so that it performs certain checks, and prevents some software from automatically loading or opening. The following article will help:

OS X El Capitan: Start up in safe mode

And then, test in a new user account and see if you get the same message. This helps isolate the issue from the current user on your Mac. The following article will help:

How to test an issue in another user account on your Mac

Best Regards.