Q: Can't connect to the Software Update server (swscan.apple.com)

Please triple-click the word "telnet" in the line below on this page to select the whole line:

telnet swscan.apple.com 443

Copy the selected text to the Clipboard by pressing the key combination command-C.

Launch the built-in Terminal application in any one of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Paste into the Terminal window by pressing command-V. I've tested these instructions only with the Safari web browser. If you use another browser, you may have to press the return key after pasting.

You should almost instantly get three lines of output below what you entered, the last of which is this:

Escape character is '^]'.

If there's no output within ten seconds, consider that a failure. Otherwise, please post the output in a reply. You can then quit Terminal.

Please read this whole message before doing anything.

This procedure is a diagnostic test. It’s unlikely to solve your problem. Don’t be disappointed when you find that nothing has changed after you complete it.

The purpose of the test is to determine whether the problem is caused by third-party software that loads automatically at startup or login, by a peripheral device, by a font conflict, or by corruption of the file system or of certain system caches.

Disconnect all wired peripherals except those needed for the test, and remove all aftermarket expansion cards, if applicable. Start up in safe mode and log in to the account with the problem.

Note: If FileVault is enabled in OS X 10.9 or earlier, or if a firmware password is set, or if the startup volume is a software RAID, you can’t do this. Ask for further instructions.

Safe mode is much slower to start up and run than normal, with limited graphics performance, and some things won’t work at all, including sound output and Wi-Fi on certain models. The next normal startup may also be somewhat slow.

The login screen appears even if you usually login automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin.

Test while in safe mode. Same problem?

After testing, restart as usual (not in safe mode) and verify that you still have the problem. Post the results of the test.

If you've installed any third-party "anti-virus" or "firewall" software, please remove it according to the developer's instructions after backing up all data. Such software should not be used on a Mac. If you don't know what's installed, see below.

1. This procedure is a diagnostic test. It changes nothing, for better or worse, and therefore will not, in itself, solve the problem. But with the aid of the test results, the solution may take a few minutes, instead of hours or days.

The test works on OS X 10.7 ("Lion") and later. I don't recommend running it on older versions of OS X. It will do no harm, but it won't do much good either.

Don't be put off by the complexity of these instructions. The process is much less complicated than the description. You do harder tasks with the computer all the time.

2. If you don't already have a current backup, please back up all data before doing anything else. The backup is necessary on general principle, not because of anything in the test procedure. Backup is always a must, and when you're having any kind of trouble with the computer, you may be at higher than usual risk of losing data, whether you follow these instructions or not.

There are ways to back up a computer that isn't fully functional. Ask if you need guidance.

3. Below are instructions to run a UNIX shell script, a type of program. As I wrote above, it changes nothing. It doesn't send or receive any data on the network. All it does is to generate a human-readable report on the state of the computer. That report goes nowhere unless you choose to share it. If you prefer, you can act on it yourself without disclosing the contents to me or anyone else.

You should be wondering whether you can believe me, and whether it's safe to run a program at the behest of a stranger. In general, no, it's not safe and I don't encourage it.

In this case, however, there are ways for you to decide whether the program is safe without having to trust me. First, you can read it. Unlike an application that you download and click to run, it's transparent, so anyone with the requisite skill can verify what it does.

You may not be able to understand the script yourself. But variations of it have been posted on this website thousands of times over a period of years. The site is hosted by Apple, which does not allow it to be used to distribute harmful software. Any one of the millions of registered users could have read the script and raised the alarm if it was harmful. Then I would not be here now and you would not be reading this message. See, for example, this discussion.

Another indication that the test is safe can be found in this thread, and this one, for example, where the comment in which I suggested it was recommended by one of the Apple Community Specialists, as explained here.

Nevertheless, if you can't satisfy yourself that these instructions are safe, don't follow them. Ask for other options.

4. Here's a general summary of what you need to do, if you choose to proceed:

☞ Copy a particular line of text to the Clipboard.

☞ Paste into the window of another application.

☞ Wait for the test to run. It usually takes a few minutes.

☞ Paste the results, which will have been copied automatically, back into a reply on this page.

These are not specific instructions; just an overview. The details are in parts 7 and 8 of this comment. The sequence is: copy, paste, wait, paste again. You don't need to copy a second time.

5. Try to test under conditions that reproduce the problem, as far as possible. For example, if the computer is intermittently slow, run the test during a slowdown.

You may have started up in safe mode. If the system is now in safe mode and works well enough in normal mode to run the test, restart as usual before running it. If you can only test in safe mode, do that.

6. If you have more than one user, and only one user is affected by the problem,, and the affected user is not an administrator, then please run the test twice: once while logged in as the affected user, and once as an administrator. The results may be different. The user that is created automatically on a new computer when you start it for the first time is an administrator. If you can't log in as an administrator, test as the affected user. Most personal Macs have only one user, and in that case this section doesn’t apply. Don't log in as root.

7. Load this linked web page (on the website "Pastebin.") The title of the page is "Diagnostic Test." Below the title is a text box headed by three small icons. The one on the right represents a clipboard. Click that icon to select the text, then copy it to the Clipboard on your computer by pressing the key combination command-C.

If the text doesn't highlight when you click the icon, select it by triple-clicking anywhere inside the box. Don't select the whole page, just the text in the box.

8. Launch the built-in Terminal application in any one of the following ways:

☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)

☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.

☞ Open LaunchPad and start typing the name.

Click anywhere in the Terminal window to activate it. Paste from the Clipboard into the window by pressing command-V, then press return. The text you pasted should vanish immediately.

9. If you see an error message in the Terminal window such as "Syntax error" or "Event not found," enter

exec bash

and press return. Then paste the script again.

10. If you're logged in as an administrator, you'll be prompted for your login password. Nothing will be displayed when you type it. You will not see the usual dots in place of typed characters. Make sure caps lock is off. Type carefully and then press return. You may get a one-time warning to be careful. If you make three failed attempts to enter the password, the test will run anyway, but it will produce less information. If you don't know the password, or if you prefer not to enter it, just press return three times at the password prompt. Again, the script will still run.

If the test is taking much longer than usual to run because the computer is very slow, you might be prompted for your password a second time. The authorization that you grant by entering it expires automatically after five minutes.

If you're not logged in as an administrator, you won't be prompted for a password. The test will still run. It just won't do anything that requires administrator privileges.

11. The test may take a few minutes to run, depending on how many files you have and the speed of the computer. A computer that's abnormally slow may take longer to run the test. While it's running, a series of lines will appear in the Terminal window like this:

    Test started

        Part 1 of 4 done at: … sec
        …
        Part 4 of 4 done at: … sec

    The test results are on the Clipboard.

    Please close this window.

The intervals between parts won't be exactly equal, but they give a rough indication of progress.

Wait for the final message "Please close this window" to appear. If you don't see it within about 15 minutes, the test probably won't complete in a reasonable time. In that case, press the key combination control-C or command-period to stop it. Then go to the next step. You'll have incomplete results, but still something. If you close the Terminal window while the test is still running, the partial results won't be saved and you'll have to start over.

12. When the test is complete, or if you stopped it because it was taking too long, quit Terminal. The results will have been saved to the Clipboard automatically. They are not shown in the Terminal window. Please don't copy anything from there. All you have to do is start a reply to this comment and then paste by pressing command-V again.

At the top of the results, there will be a line that begins with the words "Start time." If you don't see that, but instead see a mass of gibberish, you didn't wait for the "close this window" message. Please wait for it and try again.

If any private information, such as your name or email address, appears in the results, anonymize it before posting. Usually that won't be necessary.

13. When you post the results, you might see an error message on the web page: "You have included content in your post that is not permitted," or "The message contains invalid characters." That's a bug in the software that runs this website. Please post the test results on Pastebin, then post a link here to the page you created.

If you have an account on Pastebin, please don't select Private from the Paste Exposure menu on the page, because then no one but you will be able to see it.

14. This is a public forum, and others may give you advice based on the results of the test. They speak for themselves, not for me. The test itself is harmless, but whatever else you're told to do may not be. For others who choose to run it, I don't recommend that you post the test results on this website unless I asked you to.

______________________________________________________________

Copyright © 2014, 2015 by Linc Davis. As the sole author of this work (including the referenced "Diagnostic Test"), I reserve all rights to it except as provided in the Use Agreement for the Apple Support Communities website ("ASC"). Readers of ASC may copy it for their own personal use. Neither the whole nor any part may be redistributed.

Hey Linc!

I've been having this exact same issue (cannot run App Store updates - "can't connect to apple update server".  If you don't mind helping me as well - you'd be my hero!!

Here are a few of the suspect console lines that popped up when I tried:

********************

9/29/16 4:32:21.593 PM softwareupdated[240]: tcp_connection_host_start 6 DNSServiceCreateConnection failed: -65563

9/29/16 4:32:21.593 PM softwareupdated[240]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 1

9/29/16 4:32:22.666 PM softwareupdated[240]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 2

9/29/16 4:32:23.738 PM softwareupdated[240]: dnssd_clientstub ConnectToServer: connect()-> No of tries: 3

9/29/16 4:32:24.812 PM softwareupdated[240]: dnssd_clientstub ConnectToServer: connect() failed path:/var/run/mDNSResponder Socket:6 Err:-1 Errno:13 Permission denied

9/29/16 4:32:24.812 PM softwareupdated[240]: tcp_connection_host_start 6 DNSServiceCreateConnection failed: -65563

9/29/16 4:32:24.882 PM storeuid[736]: UIServiceDelegate: Accepting new connection <NSXPCConnection: 0x7fa88b21a2d0> connection from pid 16015 with interface <UIServiceInterface: 0x7fa88b21ac40> (PID 16015)

9/29/16 4:32:24.905 PM storeaccountd[410]: AccountServiceDelegate: Accepting new connection <NSXPCConnection: 0x7fc302485a00> connection from pid 16013 with interface <AccountServiceInterface: 0x7fc3024110b0> (PID 16013)

9/29/16 4:32:25.000 PM kernel[0]: Sandbox: softwareupdated(240) deny file-write-create /private/var/folders/zz/zyxvpxvq6csfxvn_n00000s0000068/C/com.apple.SoftwareUpda te.SUUpdateServiceDaemon.state.sb-886572fb-dWLKrx

9/29/16 4:32:30.617 PM com.apple.WebKit.WebContent[16015]: <NSXPCConnection: 0x7fcc00d3a690> connection to service named com.apple.storeassetd: Warning: Exception caught during decoding of received reply to message 'incompatibleUpdatesWithReplyBlock:', dropping incoming message and calling failure block.

Exception: Exception while decoding argument 0 (#1 of invocation):

<NSInvocation: 0x7fcc0ac1e3a0>

return value: {v} void

target: {@?} 0x0 (block)

argument 1: {@"NSArray"} 0x0

Exception: value for key 'NS.objects' was of unexpected class 'CKUpdate'. Allowed classes are '{(

    NSArray,

    NSNumber,

    NSDictionary,

    NSNull,

    NSDate,

    NSString,

    NSData

)}'.

9/29/16 4:32:30.619 PM com.apple.WebKit.WebContent[16015]: <NSXPCConnection: 0x7fcc00d3a690> connection to service named com.apple.storeassetd: Warning: Exception caught during decoding of received reply to message 'incompatibleUpdatesWithReplyBlock:', dropping incoming message and calling failure block.

***************

and just a bit before this I ran the test you described and pasted the results to this Pastebin.

thanks in advance!!

Joey

ps - I was not sure whether starting a new thread or pasting into this one was the preferred etiquette - my apologies if I chose wrong!