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When Finder is operating on a file or folder on the system, the file/folder is greyed out and unable to be opened, as well as unable to be trashed. This is most notable when copying or moving a file or folder using Finder; whilst the operation is in progress the destination file/folder is shown in grey. Finder is aware that the destination file/folder is currently in an operation by setting the creation date of the file or folder to the kMagicBusyCreationDate, which is 08:34:56 on 1946-02-14 (+0000).

What is the significance of this date and time? When I discovered that a date is used for the aforementioned purpose by Finder, I expected it to be something relating to the Unix timestamp/epoch, etc. but nothing seems to be standing out to me as a reason for this date/time being chosen, being far back beyond 1970.

I have found in Finder.h, the following comment is provided, yet this does not provide the significance of the specific date/time that was selected either:

Use this date as a file's or folder's creation date to indicate that it is temporarily busy (while it is being downloaded or installed, for example). This prevents Finder from trying to change the item's attributes before it is fully created (Finder 8.5 and 8.6 check file creation dates; later Finders may check folder creation dates as well). 

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Since this is a really interesting question, would you please update the link to Finder.h? – Behdad Oct 7 '15 at 11:48
It strangely redirects to which returns a 404. I added the /o/se/ manually to the URL and it worked fine. (Tested with both Safari and Chrome, same behaviour.) – Behdad Oct 7 '15 at 12:22
@Behdad Thanks, I reproduced this on another computer. Seems I've broken something with the redirecting to https. I'll have a look into why this is happening, but in the meantime I appreciate the edit! – grgarside Oct 7 '15 at 20:26
up vote 33 down vote accepted

I heard that it was the day ENIAC was revealed to the world:

The completed machine was announced to the public the evening of February 14, 1946 and formally dedicated the next day at the University of Pennsylvania

The theory being that there were no "files" in existence prior to that date.

With regard to the time, 0x4F3AFDB0 (from Finder.h above) mod 86400 (seconds in a day) is 2096. 2096 seconds after midnight is 12:34:56 AM. This is almost certainly the intent: that it reads "123456" on the specified day when time zone adjusted.

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Interesting; do you have a citable source for this? (and do you have a theory for the time?) – grgarside Aug 8 '14 at 18:20
There are a few reliable sources regarding the date e.g., but the lack of citable source for the time puts it in the "believable, but not 100% verifiable" category for me. – Laconic Droid Aug 8 '14 at 18:44
As far as the time component, I wonder if 08 is time zone adjusted? if time shifted 4 hours one way or 8 the other way the time could read 12:34:56 – Tyson Aug 8 '14 at 18:57
0x4F3AFDB0 (the value from that Finder.h file) mod 86400 (seconds in a day) = 2096. 2096 seconds after midnight is 12:34:56 AM. This is almost certainly the intent: that it reads "123456" on the specified day. – Tim S. Aug 8 '14 at 21:03
Best.Valentines.Day.Present.Ever! Now we know what the original hello world program was supposed to say: "Hello world. I love you." But probably there wasn't enough RAM... – Floris Aug 8 '14 at 23:27

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