Network Diagnostics app missing

ALT key and click on Wifi icon at menu bar!

In Finder on a Sierra machine, just go to /System/Library/ and copy the needed files onto your thumbdrive. Some files are in /System/Library/CoreServices/ and some are in /System/Library/PrivateFrameworks/. Then follow the instructions I posted earlier (but note that NetworkDiagnosticsUI.framework belongs in /System/Library/PrivateFrameworks/, not /System/Library/Frameworks/).

Open network utility via spotlight , see that link status should be : Active

So... since I didn't have SetupAssistantFramework from Yosemite, I figured I'd just install the three files missing in High Sierra. I disabled SIP, inserted Network Diagnostics, Network Setup Assistant and Network diagnostics UI.framework

where they should be. I figured this wouldn't work so I didn't bother with changing ownership. Rebooted... and it DID work. Can't imagine why it's working, or when it will stop (obviously at the most critical time) but for now I'm a happy camper. Thanks again Keith.

I included this in an earlier post on this thread; you can give feedback to Apple here: Feedback - macOS - Apple

The more people who complain, the more likely Apple is to listen.

You almost certainly need to have System Integrity Protection disabled to do this. I already had SIP disabled when I followed your steps.

In addition to changing SetupAssistantFramework.framework, you also need to change SetupAssistantSupport.framework, just below it.

And to do everything correctly, the owner of all 4 files should be changed to root and the permissions set to rwxr-xr-x.

Finish by re-enabling SIP.

Wireless Diagnostics is not the same as Network Diagnostics. Go to /System/Library/CoreServices/Network Diagnostics.app. You will not find it in High Sierra. See my instructions on how to restore it (and the Network Setup Assistant) elsewhere in this thread.

@Shawnnafromwa, assuming you have a Time Machine or other backup of your Sierra installation, you can find fairly detailed instructions in my previous post on this thread here (always read the whole thread): Re: Network Diagnostics app missing

My instructions assume a few things, like how to disable and enable System Integrity Protection and how to change ownership and permissions on files. You can Google how to do those - there are plenty of sites that explain how.

As danuke said, if you can't find a backup of Sierra, then you're out of luck. Make sure you give feedback to Apple in any case!

Regarding ISP failed , open mail application > connection doctor .

Only rotating circles will be observed in front of SMTP and IMAP connections and there will be no red dots , it means server is down .

The only one setting- network diagnostic tool , users are looking has been distributed .

@stolzius, Good job thus far. It wasn't my intent to explain how to change ownership and permissions on the files because that's info you can Google or find in any decent guide to macOS. You need to change ALL of the files you restored to the System folder because, as you observed, all files in that folder should be owned by the system. However, while Finder displays the owner as "System," technically they belong to the root user. Permissions rwxr-xr-x means that the owner (root) can read, write, execute; the group (staff) can only read & execute; everyone else can only read & execute. So Google "how to change file owner to root on Mac" and "how to change file permissions on Mac." If you can find the book Take Control of Permissions in Snow Leopard, by Brian Tanaka, it explains everything you need to know. Even though it was written for Snow Leopard, nothing has changed since then. If after researching you still have questions, post back and I will try to answer.

Indeed this useful tool seems to be missing.

The solution is to create 2 Wifi frequencies. Usually this means adding a 5 GHz one. Whenever there are Wifi connection problems, just swap between the 2 Wifi frequencies and the problem is solved within several seconds.

Steven, You're sure you're still on Sierra and not High Sierra, right? If all you want is Network Diagnostics, you need only the following 2 files:

/System/Library/CoreServices/Network Diagnostics.app

/System/Library/PrivateFrameworks/NetworkDiagnosticsUI.framework

Copy the path of each file without the file name (e.g., /System/Library/CoreServices/), then in Finder, press Shift-Command-G, which brings up "Go to the folder." Paste the path in the box and click Go. Then in each folder find the desired file and drag it to an external drive. Then follow the rest of the instructions.

Hi Poppy, Definitely make your thoughts known to Apple. Our only hope is that the volume of complaints will force them to address this. I share your angst. But I urge you to consider following Keith's tips. Going slowly, step by step, anyone can do this. Most of us (especially us seniors) have a little luddite in us, but don't be afraid of terminal. I can't count how many times I've entered commands with typos (or worse) and almost always, the most that happens is your command is rejected and you start over. Sheepishly (but all too typical for me), I admit that when I copied and pasted Keith's ownership commands, in one case I inadvertently included part of the line that followed. Simple to correct. Most likely you'll be better than me, and in no time, you'll have Network Diagnostics residing happily on your desktop. Good luck.

Hi Poppy - I concur with Maria's comments. I followed Keith's instructions to the letter and everything worked perfectly so I now have Network Diagnostics and Network Setup Assistant working again in High Sierra. Once I'd set them up I moved the apps to the Applications/Utilities folder so they're easy to find and use. I've also complained to Apple but I doubt they'll respond, as based on their recent ads it looks like they're phasing out the Mac operating system (which ia a wonderful Linux implementation) in favour of everything being iOS (heaven help us!). Good luck and let the forum know when you've successfully reinstalled the apps - and we'll also help if you get stuck.

Network Utility is not Network Diagnostics.