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Time Machine not backing up external drive to external drive

Hi,


I have a M1 Mac Mini 256 GB and a Samsung 2 TB external ssd for photos and files. SSD has about 1 TB of data.


I have used Time Machine to back this up to another external drive (5 TB HDD).


I just noticed this weekend that the folder that is supposed to contain the external ssd, is empty on the backup. And it has been empty going back a few months. I think in January it had visible data on SSD.


If I enter Time Machine "Macintosh HD" is perfectly browsable, but if I open the folder with the name of the SSD drive, it contains nothing.


It is copying the right amount of data in the HDD and takes about the time I'd imagine it to copy 1 TB to a spinning drive.


Tried so far:


  • Set up a new 4 TB HDD for TM, same thing happens
  • Reinstall Mac OS, no effect
  • Checked that the external SSD is not on exlusion list in TM, it was not, but set it and removed again, no effect


5 TB drive gave an alert on reallocated sectors, but still the same happens with the new 4 TB disk, no ssd data in the folder. I checked SSD with Samsung Magician on Windows and it reports as healthy.


Anything more I could try?

Mac mini (M1, 2020)

Posted on Mar 26, 2023 12:24 PM

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Question marked as Top-ranking reply

Posted on Mar 28, 2023 12:27 PM

Digging this further I noticed that "Get Info" for the external drive in Time Machine says "No access" and I couldn't cd into that folder in terminal. Except for when enabling root user and all the files are there.


Now I need to figure out why TM screws access rights.


Solved. I added Read & Write rights to "admin" on the external drive and after that I saw the files in the TM backup.


No idea on what happened before and why it changed. Because it worked at some point.

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2 replies
Question marked as Top-ranking reply

Mar 28, 2023 12:27 PM in response to anonpig

Digging this further I noticed that "Get Info" for the external drive in Time Machine says "No access" and I couldn't cd into that folder in terminal. Except for when enabling root user and all the files are there.


Now I need to figure out why TM screws access rights.


Solved. I added Read & Write rights to "admin" on the external drive and after that I saw the files in the TM backup.


No idea on what happened before and why it changed. Because it worked at some point.

Time Machine not backing up external drive to external drive

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