Erasing a partition

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Hi,

It would seem that Time Machine got a little unhappy with me undocking my laptop from my external hard drive and now Time Machine will no longer work. I use an external drive for this and it is separated into 3 partitions, one of which is my Time Machine backup. I've had no problems for over a year using it like this, but i can't seem to repair the Time Machine partition. That being the case, i am wondering if i can erase just that partition, and perhaps re-assign it to get it working again. Can anyone confirm that erasing the one partition will not erase the other two? I don't know if it will do it again once i unplug the laptop, but it's worth a shot.
 
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Well, i went ahead and winged it and it erased just that partition. And Time Machine is once again backing up.
 
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Aaaaaand we're back to Time Machine not working after disconnecting the computer again. I never had this issue before, so i'm not sure what has changed. I've been on the same OS all year.
 

Rod


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You could try erasing and reformatting again but this time give the TM partition a different name eg. Time Machine #2 then select it as the TM backup again. Just so we know that your computer sees it as a different location.
Personally I would offload the data on the other two partitions, either onto your computer itself or another EHD. Then, erase the the whole EHD at the Media (name of the external drive eg Samsung...) level. This will remove the partitions and ensure the formatting is the same throughout.
The first solution may work but really having 3 partitions on an EHD really is putting all your eggs in one basket. Better would be three EHD's connected with a hub. Obviously this is more expensive but so is losing valuable data.
 
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Thanks for the info. Two partitions on the drive are actually secondary backups and then the time machine backup is the third.

After opening up time machine in the system preferences, i hit the select disc button and it had what is more or less my Time machine back up, and then it showed the three partitions with Time Machine backup as one of them. I was able to select that and it backed up properly. I wasn't able to do that with my previous issue, but it never did ask me to do this earlier in the year when i would disconnect it.

I've been on the fence now for a while about going to a Mac Mini for the home office, so perhaps if i did that, then i wouldn't be disconnecting the drives all of the time.
 

Rod


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I think that would be the ultimate solution. You could keep your MB for portability and share your documents/photos across the two devices.
 
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I refrained from commenting because my experience may not apply. However, I'm running Monterey and doing Time Machine backups to two attached drives. These are 1Gb partitions on 4Gb drives and that works fine. I'm careful to dismount the drives before disconnecting and the only problem I've had is sometimes one or the other Time Machine backups fails to mount when I reconnect. I have to use Disk Utility to mount it.
 

Rod


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Just talking from my own experience here, I have never had a TM backup on a partitioned drive. Because TM constantly grows over time, erasing old backups as space diminishes and because the format of TM is different to the normal data storage on an EHD.
I have never had a TM EHD fail to mount unless there was something wrong with the EHD itself or the backup, eg. corruption. In that case I have replaced it.
Imagine the scenario that your macOS becomes damaged and needs to be reinstalled or you are simply moving to a new device. You go through the setup process with the Setup Wizard until you reach the point where you are asked if you would like to restore personal data from a backup eg Time Machine so you plug in your EHD but the TM partition wont mount. 😭
There is only one thing worse than no backup and that's a defective backup. I prefer a dedicated EHD for TM and recommend everyone do the same.
It doesn't have to be an SSD either, "spinner" HDD's are cheap these days and handle rewrites much better than SSD's.
 
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Just talking from my own experience here, I have never had a TM backup on a partitioned drive. Because TM constantly grows over time, erasing old backups as space diminishes and because the format of TM is different to the normal data storage on an EHD.

I have never had a TM EHD fail to mount unless there was something wrong with the EHD itself or the backup, eg. corruption. In that case I have replaced it.

I use a partition because Time Machine will grow to fill the available space so I limit the space. 1Tb is enough and my drives are 6Tb.

I have two time machine backups for redundancy and usually they both mount. One or the other ALWAYS does. I also do a daily SD! backup to a data drive and a weekly SD! backup to another data drive. I'm pretty paranoid about this stuff.
 

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