Calendar sync problem Mac → iPhone

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Zorba_le_grec Author

Level 3

581 points

Calendar sync problem Mac → iPhone

I am using Calendar on my Mac and iPhone only.

I don't use iCloud.

My way of using Calendar is from the Mac only. Then regularly I synchronize them through a

simple USB connection, and my iPhone get an exact copy of my Mac Calendar.

To make it short, for all my calendars, my Mac is the master, and my iPhone a slave copy.

I usually never touch any of my calendars from the iPhone ( because lack of basic functions, and the risk of the kind of accident I describe here and which made me lost critical informations ).

Recently I added some flights numbers with their schedule times and locations on my Mac.

Then I synchronized them and all my flights were on my iPhone.

Then I made a stupid error I didn't discover immediatly. I removed one of my flights on my iPhone. Most probably through an accidental selection of the event, and an accidental delete.

Then I added another stupid error. To recover it as fast as possible, I connected my Mac and my iPhone

and ran a synchronization.

Then the required flight schedule was still not on my iPhone but had also been erased on my Mac.

This kind of accident arrives to me pretty often, most notably when I am in a hurry.

I am looking now for 2 levels of ideas, suggestions, solutions:

On very short time how may I undo a destructive synchronization?
With some more time, how may I recover my flight schedule on my Mac? ( My Time Machine is at home on purpose and I am travelling for a certain time far from home in a risky context ). I am a system engineer and could dig inside the history of my calendars database with local backup copies.
On the long term how may I fix the synchronization mechnism so that it could never cause a destruction on my master ( which is my Mac )?

MacBook Pro 15″

Posted on Jun 10, 2024 3:19 PM

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Answer 1

Zorba_le_grec Author

Level 3

581 points

Jun 23, 2024 9:37 AM in response to Zorba_le_grec

Finally I found an easy escape to this problem of a single event accidentally deleted

to recover without loosing the events which were registered after the accident.

This require the use of the Time Machine disk ( but not the Time Machine application ), and some investigation with the help of direct access inside the Time Machine correct version of ~/Library/Calendars:

Go into the Time Machine disk ( don't enter Time Machine ), and inside

    Backups.backupd/disk_name/date/Library/Calendars

where date is the date of the last back before the accidental destruction

2. Identify the correct calendar uniq name by looking at some of the ".ics" which are inside ( one for each

event ),

3. find inside this 1234ABCD-12AB-09EF-01234567CDEF.calendar, which ".ics" is the accidentally deleted

one, be careful not to move any file within the Time Machine tree structure,

4. copy this .ics file it in ~/tmp, let's say ~/tmp/24-06-2024.ics ,

5. start Calendar,

6. import this ~/tmp/24-06-2024.ics .

This simple recipe let me recover the accidentally deleted event, and avoided me the destruction

of the following events if I had used Time Machine to go back into the past version of the 24/06/2024.

I fully documented this simple receipe for the next time this kind of accident will happen again.

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Answer 2

6x6

Level 7

20,961 points

Jun 10, 2024 4:05 PM in response to Zorba_le_grec

On your iPhone, if you catch the deletion soon enough, shake vigorously the iPhone to undo the deletion. It's unclear how long one is able to undo a change, though.

On your Mac, restore the /Users/[your username]/Library/Calendars folder using Time Machine.

There is no built-in way to lock a calendar as read-only on the iPhone. There would be a roundabout way using 2 Apple IDs and iCloud (using the share calendar functionality) but you'd have to use iCloud and the iPhone would have to use another Apple ID, which is not ideal.

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Answer 3

6x6

Level 7

20,961 points

Jun 23, 2024 9:34 AM in response to Zorba_le_grec

Hi Zorba_le_grec, that’s a great way of doing it. Thanks for having shared this with the community!

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Answer 4

Zorba_le_grec Author

Level 3

581 points

Jun 11, 2024 4:17 AM in response to 6x6

6x6: thank you.

I tried the shaking trick on my iPhone, but it was too late. Moreover, it just proposed to undo the last local modification.

I also tried the 'Edit > Undo' within Mac Calendar application in correct time, but it cannot undo a destructive synchronization.

The use of Time Machine is not possible now ( I kept my Time Machine disk at home because I am travelling

in a risky context ). Moreover, I am sure a Time Machine will be also destructive because it will destroy the other

modification I made on my Mac since. I am not aware of a way to use Time Machine to restore a precise modification in time and nothing else, a kind of incremental restore with a clear information of the user of what is

restored.

I won't even think to try iCloud despite your nice idea. I had to many users to save of what they lost due

to their lack of clear understanding of what iCloud was transferring and in which direction 😎. And as you stated

rightfully it is "not ideal" and I am sure I will be able to trap me with such a complex use of iCloud.

Now I am digging inside 'Library/Calendars' to find a safe path to extract the information I unwillingly destroyed.

Anyway, I highly appreciate your clear understanding of my problem and your answer on multiple plans.

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Calendar sync problem Mac → iPhone

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