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Introducing Simon 5!

Simon version 5 is now available. It is a massive update, introducing a much-requested feature: syncing the Simon data between multiple Macs, plus a Simon Status service, a Link Checker filter, improved Find filter, iMessage and Speak Error notifiers, a new app icon, and much more.

Important: please note that Simon 5 requires a minimum of macOS 10.12 (Sierra), and is a paid upgrade from Simon 4. Purchasers since September 1, 2020 automatically get a version 5 license (that also works in previous versions).

Read the Simon What's New page for details.

Check on Web (HTTP) and Specific DNS hangs

Hi David and Daniel,

I just got my Specific DNS working properly on my MacBook Pro (using your fix).

I let my laptop run all night monitoring a Web (HTTP) and Specific DNS check. This morning I looked at the Simon Monitor and noticed that both test had hung when they encountered a failure. I have attached a screen shot to show what I see. Please note that both tests run ever 1 minute (success or failure......maybe thats the issue).

Also note the following (I have actually included two attachments).
- One with Web (HTTP) highlighted where Check now is available on the top menu.
- Second where Specific DNS is highlighted and only Stop Check is available on the top menu.

Any thoughts? Is this another issue maybe related to running on a MacBook Pro?


Picture 6.png86.72 KB
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David Sinclair's picture

Re: Check on Web (HTTP) and Specific DNS hangs

Weird. It should have timed out after two minutes, even if the check didn't complete properly.

The Web (HTTP) test is just waiting for the Specific DNS one to finish. Simon only runs one check at a time, to get the most accurate results. Stopping the runaway one would restore normal operations, though of course that shouldn't be necessary.

Were there any Simon-related lines in the Console log? An exception at the wrong point could have conceivably interfered with normal operations.

Weird hangs

Hi David,

When you ask about the console log, I assume you mean the Failure Log at the bottom of the Simon Monitor window.

I did not see anything odd but I was not looking previously. I cleared all stats since the last message to you. Let me continue monitoring and let you know if I see any strange entry the next time it hangs.

Thanks for explaining the sequencial nature of multiple tests. Means I should only really worry about the leading test that hangs.

Hope to send more info. soon.


David Sinclair's picture

Console log

Sorry, I should have been more clear.

By Console log I meant as displayed in the Console application, which is at /Applications/Utilities/Console.

Launch that, and type "simon" into the Filter toolbar field. It'll display just Simon-related lines. If there aren't any, check that the log is displaying far back enough; you can press Cmd-R to load more. If there are some, please either paste in a reply here or via email.


Ooops, David beat me to it.

Ooops, David beat me to it.

Console log


I just checked. The earliest entries in the Console log do not go back far enough to when I had the problem (3/3/07 night). Let me wait for another hang and then check the Console log to see if there is something there.

Does that make sense to you or do you still want me to send all the info. in the log.


David Sinclair's picture

Re: Console log

You can load more via Cmd-R. Or send the entire file via email; simply click on the icon in the titlebar and drag to an email message. Or wait till it happens again, if you prefer (and if it does).

Console log results

Hi David,

Ok I think I have something. Exact same issue did not occur but I think it is related. Keep this background information in mind.

- I am on a laptop but I made sure that energy saver, sleep, etc, are not invoked and that the laptop is plugged in to the AC adapter

- I stopped using my computer around 10pm last night.

- At 11:07pm the last checks appear to have worked properly.

- When I checked this morning and hit the spacebar to stop the screen saver, there was a que message under the next test but the tests then immediately ran.

- However when looking at the previous checks it was obvious that between 11:27pm and this moring (~6am) nothing had been checked.

- The console log shows entries at approx. 11:28pm.

Do these entries mean anything to you? See below. I just sent the entries immediately after the events of interest.


2007-03-05 23:08:08.090 Simon[1274] startForSite: DNS withPlugin: Specific DNS exception: NSInvalidArgumentException (*** -[NSCFDictionary setObject:forKey:]: attempt to insert nil value)
2007-03-05 23:10:08.093 Simon[1274] NSInvalidArgumentException: *** -[NSConcreteTask interrupt]: task not launched
2007-03-05 23:10:08.197 Simon[1274] *** NSTimer discarding exception '*** -[NSConcreteTask interrupt]: task not launched' that raised during firing of timer with target 165809e0 and selector 'timeout:'
2007-03-06 01:47:09.774 Simon[1274] NSInvalidArgumentException: *** -[NSConcreteTask interrupt]: task not launched
2007-03-06 01:47:09.988 Simon[1274] Exception raised during posting of notification. Ignored. exception: *** -[NSConcreteTask interrupt]: task not launched
2007-03-06 05:49:53.101 Simon[1274] NSInvalidArgumentException: *** -[NSConcreteTask interrupt]: task not launched
2007-03-06 05:49:53.152 Simon[1274] *** -[NSAutoreleasePool dealloc]: Exception ignored while releasing an object in an autorelease pool: *** -[NSConcreteTask interrupt]: task not launched

David Sinclair's picture

Re: Console log results

Thanks for that, it's very helpful.

That console log shows that the dig unix task used by the Specific DNS plug-in wasn't launched (at 23:08), so then timed out two minutes later (at 23:10), but didn't time out either, as the task hadn't started.

I'm not sure why the task wasn't launched. I have a feeling it may be related to the "too many files open" issue that 2.2.1 fixed, even though that error isn't given. So I'll create a new build to address that, and email it to you to try.