Time machine backups - if I delete a file on my disk, will this "sync" on my next backup or will it remain?

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Level 1

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Time machine backups - if I delete a file on my disk, will this "sync" on my next backup or will it remain?

Dear all,

I run frequent time machine backups on an external hard drive (WD).

Question: do backups overwrite previous backups with a new snapshot of the computer, or do backups only ADD new elements and keep deleted elements unchanged meaning those elements are kept from previous backups.

Eg.:

i) I have three Word documents on my computer;

ii) I do a time machine backup;

iii) I delete one of the Word documents;

iv) I do a second time machine backup;

v) I create a new Excel document;

vi) I do a third time machine backup

In this case, if I restore my files, will I have all three Word documents (including the one I deleted) plus the new Excel document, even though I've done backups after deleting one of the Word documents?

For lack of better words: do backups only "add" new files, or do they also "delete" files which have been deleted from the disk

Reason for asking: I've been removing many files from my computer and backing up regularly and I don't want the backup to take a snapshot of my latest computer disk but rather store everything I delete and add new files in increments as I create them.

Apologies from the poorly worded question. Hopefully this will shed light for others as well. Thanks very much in advance.

Time Machine-OTHER, OS X Yosemite (10.10.4)

Posted on Apr 13, 2016 4:00 PM

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Answer 1

Apr 13, 2016 4:37 PM in response to Simounsays

The following may help: http://pondini.org/TM/Clones.html

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Answer 2

Linc Davis

Level 10

209,739 points

Apr 13, 2016 6:21 PM in response to Simounsays

Time Machine is a backup tool, not an archiving tool. It gives you a window of time in which to recover data that has been lost from the backup sources. You can't rely on it to preserve files that you want to keep indefinitely. Any such files must be backed up along with the rest of your original data. Files that you delete from the source volume(s) will eventually be deleted from the backups, after a variable delay that depends on your usage pattern and the size of the backup volume.

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Answer 3

dwb

Level 7

33,244 points

Apr 14, 2016 4:16 AM in response to Simounsays

TimeMachine is making hourly backups of your computer (as long as the computer is connected to the TimeMachine device) and each new backup contains just those files that were added or edited since the last backup. At scheduled periods hourly backups are amalgamated to create a single backup representing a day, thereby losing the hourly restore points. Also at another point daily backups are amalgamated to create a restore point representing a week. Further if at any time TimeMachine cannot complete its job due to a lack of space the oldest backup(s) will be deleted to make room.

TimeMachine is not an archiving tool. As noted above a period of hourly updates will be trimmed to create a single backup point to represent the day and daily backups will be trimmed to create a single backup point to represent a week and old backups will be erased to create space for new backups. For this reason you can only be sure that TimeMachine will have backups of the files currently on your computer. If you delete a file from your computer it may be found in TimeMachine at a later date but there is no guarantee that it will be. The only guarantee is that backups of files currently on your computer will be in the backup pool.

For this reason you should never delete something from your computer with the expectation you can restore it later from TimeMachine. For this you will need archiving backup software.

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