Recovering a lost iCal calendar

November 21, 2022 5:59 AM

For 10+ years in my Mac Calendar, I had been saving a specific calendar as sort of almanac that I called "for the record." It had, for example, a record of first snow each year, or when I started a certain project, or a historic anniversary such as the fall of Constantinople or Thelonious Monk's birthday. One day this spring, after a couple of chaotic months at work, I noticed that somehow that particular calendar disappeared. I now have a bit of time to fiddle with trying to recover this stuff. But I cannot get the data out of a cache file.

The calendar disappeared too long before I noticed it to get it back using the normal iCloud restore.

I also tried my backblaze backup, but I could not determine which file was the right one, and now I am waaaay past the 30 day backup, anyway.

However, maybe a month and a half after the calendar disappeared, I did find on my harddrive a file called “calendar cache” and I made a copy of it. Opening it with BBedit confirmed that some of the information I was looking for was in there.

How can I convert that 120+ MB file into something structured so that I can import, convert or use the information that is stashed away in there? I can do some basic grep, text data munging, etc. I am not afraid to play around with the Mac or an online tool. I don’t want to spend more than $10 on fixing this, if possible. I have the usual computer tools (bbedit, ms office, nisus), and so on

posted by nothing.especially.clever to Computers & Internet (3 answers total)

I think "calendar cache" is an SQLite database, so you should be able to open it with something like SQLite Browser. Not sure what you'll find, hopefully it's easily understandable.
posted by samj at 6:45 AM on November 21, 2022

I'm not a Mac person, but I've worked with a lot of calendar stuff, and was connected with some CalConnect (calendaring standards) folks unofficially through work with some mainframe calendar software. I found this link about restoring iCloud calendars from Time Machine that was hanging around for some reason, and I'm putting it here in case it is useful to someone who understands all of the Mac items in here (I understand what a .ics file is and how importing and exporting them works, but not Time Machine or iCloud)
posted by TimHare at 2:24 PM on November 21, 2022

Response by poster: Well, I was able to open the sqlite database, but I've got 29 tables & 98 indices. Poking around now, but have not yet found out anything useful.

this looks promising, but I can't make it work. It is from 2009, so god knows.
posted by nothing.especially.clever at 1:51 PM on December 12, 2022