Calendar is showing the wrong date in my dock

See this article If the wrong date or time is displayed in some apps on your Mac - Apple Support

Sometimes NVRAM / PRAM is to be applied .

When ever an updates arrives in App Store , it should be installed , and in system preferences > Language and region ( calendar is set Gregorian ) , if any changes have been done , click on advanced > again click on restore defaults .

In system preferences > date and time the box for date and time automatically is checked ( having correct continent in front of it ) , in time zone the box set time zone automatically using current location is checked , in the bottom your closest city should be correct .

These are the basic settings and should not be changed , and Etrecheck is the best tool to find out what is running in the system , you can use it and remove unwanted apps , malwares etc .

What I experienced is the softwares / apps / cleaners corrupt the system and main default applications .

Nothing cures this problem for me!

It comes and goes with updates of OSX.

I'm currently updating about every fortnight!!

Apple don't seem to be the company I used to know.

I'm reluctant to go onto High Seirra as I have a hybrid drive so I'm running OS X 10.12.6.

Anyone noticed similar?

Take back up of the data , erase the HD and reinstall the OS macOS Sierra: Erase and reinstall macOS

After installation don't ever install third party calendars , unidentified apps , anti virus , cleaners in your Mac ( you must have a good network speed while installation ) .

And never change settings in - by opening system preferences > date and time ( keep the default settings ) .

Wow root & branch solution tygb for a recurring niggle! Do you recognize the occurrence with different updates.

In previous years I would be tempted to follow your advice but NO anti virus software nowadays!!

You thought I am giving a meaning less sweet talk , but some Mac users are predisposed of installing these softwares so if there are problems in Mac why not to erase the HD and reinstall , you guys have a very good network speed , isn't that .

Nice lecture on updates tygb but I'm more cautious, in that bugs/errors/corruption can be in them; I always wait at least a week before updating, just cautious. Being in the App Store is not a guarantee that the download has NOT got unexpected consequence!

IF I had followed your (Dec 31, 2017 9:50 PM) "nuclear" suggestion I would still be getting my MBPro back to it's former useful self AND I wouldn't have been able to use it today to try to diagnose my problems with my iPhone and its interoperability with my MBPro.

I have not solved ALL my problems with my iPhone (running the latest iOS) BUT my Calendar is now displaying the correct date!!! I've done NOTHING, that has been suggested in this thread, what IS happening is in the "cloud" and NOT subject to human intervention. I think that I know what has happened but do you tygb?

I said that the problem was "a recurring niggle".

My Calendar on my iPhone displays the correct date!

I must have AV software on my MBPro.

Do you recognize the occurrence with different system updates?

Sometimes supernatural forces work 😁 happy new year and best wishes .

It would NOT have been a "Happy New Year" if I'd followed your suggestion tygb:(((

Putting the supernatural to one side:

Do you have ANY idea what cured this "niggle"?

You could remove it from the dock by clicking on it and hold. Then drag from dock and un click. Then go to the top go menu and open applications. Right click on the calendar and then make alias. Insert the alias in the dock.

Then something in your user account has modified ICal. Try this link. https://discussions.apple.com/thread/2607509?tstart=0

Here is something you could check on. https://support.apple.com/en-us/HT203413 Also this. https://discussions.apple.com/thread/2607509?tstart=0