Network Diagnostics won't close or force quit

I just figured it out

Go back to the network your having issues with and retry it. Once you do it will ask you to run a diagnostics again which you will then select and then promptly hit the x or quit

System preferences> network> try a network name> system preferences popup select either allow or deny> click run diagnostics again> click x or quit

Try to remove some plist :

In the system configuration the first folder is captive Network support and second last plist Networkinterfaces.plist remove both to trash .

Restart from apple logo & empty the trash .

this is the way to close wireless diagnostics external tool : Hold option key don't release it > click on wi fi icon on top menu bar > click on wireless diagnostics > quit on it , you are not closing the windows thats why it is showing three times in your dock .

close this window of screen shot

You have been set on the wrong foot alltogether here.

You are talking Network Diagnostics that will not quit.

Since the restart in Safe Mode (starting while holding the Shift key) the DiskUtility First aid tab (you have ElCapitan) did not solve the issue there has to be something else that crashes the diagnostics app. BTW this was a good advice by D.Cohen. Appreciates posts were all wrong.

As long as this is not solved I propose to quit Diagnostics by opening Activity Monitor, click the first column to make it alphabetically organised, select WirelesDiagnostics, click the little x in the top line of AM and click "forcequit".

After that first do a restart and a SMC and PRAM reset:

Reset the System Management Controller (SMC) on your Mac - Apple Support

How to Reset NVRAM on your Mac - Apple Support

If the issue still exists we go further.

Lex

Hi.

Try restarting your Mac in Safe mode:

- Shut down your Mac

- Wait until your computer turns off and after that press the Power button

- Right after you hear the startup tone, press and hold the Shift key

- Release the Shift key when you see a grey Apple sign and the progress bar below this sign

- Once you see Desktop, start a Disk Utility scan to detect and repair file system errors (don't forget to choose your main hard drive)

- Click on Verify Disk and then, if asked to fix problems, on Repair Disk

- After this, click on Verify Disk Permissions and then on Repair Disk Permissions

- After the process is finished, shut down your Mac and turn it back on after about 30 seconds

Hope this helps!

Tap on network diagnostics and do a right click and then quit or you can use key board short cut command + Q for removing a single app , if you don't want to keep in dock drag and drop the app in the centre of desktop .

Are you stating about this network diagnostics in the screen shot , if yes we have to click on continue , then have to follow the upcoming steps & in the last if connections are found to be ok . there is an option to quit but not to force quit .

First right click on network utility an option will be there - quit . click on it .

Or try to shut down the system from power button that is on extreme right corner of the computer i.e. next to F12 . keep on pressing the power button for 1.5 sec or press control + power button .

The screen will be black .

Close the lid and then again press the power button . the system will open with chime , enter user name & password then verify is the app still in dock .

Yes it was hit and trial methods so it is wiser to take back up of all mails and data .it happens sometimes if system files or apps are corrupted then it is wiser to delete old user account and form a new user account .

And the last option is wipe out the hard drive and do a fresh installation .