I need a diagnostic tool for my 2011 Focus. I'd prefer laptop based rather than a code reader type. Any recommendation?

Regards

Forscan. 

The one generally recommended on here is Forscan (free) with a modified ELM cable (about £20) from Tunnelrat Electronics.

If you only need it for diagnostic purposes then FORScan is the best by a very long way and is free to download although you will need an Extended Licence if you want to do programming, but you don't need one for Service Functions or Diagnostics. Download FORScan

Most people buy their adaptors from Tunnelrat Electronics Modified ELM327 USB (fwscart.com) . Best to get one with a automatic MS/HS Can switching. There are a lot of Chinese clones that don't work properly so I would not buy any of the ones from Amazon unless it is a genuine OBD Link one.

Personally I have an expensive Bluetooth one so I can also use it with the phone app as well as my Laptop, which is about £6 for the phone app. I keep the adaptor in the car so I can use it if I'm having trouble when away from home. There are Wi-Fi adaptors as well but you need to make sure any of the wireless ones are compatible with you phone/laptop. 

Plenty of reading on the FORScan web page and forum if you are unsure about the adaptor.   

Thanks for the replies.

Forscan - is that Windows based or will it work on a Mac?
 

You will see from the link I posted that Forscan is for Windows, Android and IOS. No mention of MacOS so no, it won't work on a Mac PC.

Yes, seen that thanks. I'll order tomorrow.
Regards