LaCie External Hard Drive Becomes Read Only

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Level 1

8 points

LaCie External Hard Drive Becomes Read Only

My LaCie 4TB HDD is used as a Time Machine backup - it has been working perfectly and did a backup less than an hour ago. When I tried to copy some files to it - not during a backup - it asked to be unlocked for access with my Admin password, which I did. The files copied successfully.

But now Time Machine is saying "Next backup: When disk is connected." And the info button says "Time Machine couldn’t complete the backup to “VED 4TB. Files can’t be copied onto the backup disk because it is read-only. You may need to repair or erase the disk using Disk Utility. If the disk can’t be repaired, select a different disk for backups.”.

I ran Disk Repair on the HDD and it did the repairs.

When I try and unlock the HDD it allows me to but it doesn't actually unlock it.

This is the second disk that this has happened with, I believe this may be a long term problem with MacOS, if someone could point me in the direction of a thread I would be grateful.

iMac (Retina 5K, 27-inch, Late 2014)

3.5 GHz Intel Core i5

MacOS High Sierra Version 10.13.6

iMac with Retina 5K display, macOS 10.13

Posted on May 24, 2019 2:36 AM

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Answer 1

Top-ranking reply

Joat the cat Author

Level 1

8 points

May 24, 2019 3:03 AM in response to rcosta887

Thank you for a speedy reply :)

I did as suggested and it unmounts, then mounts again.

However, since posting I tried the following:-

Unlocked the HDD in the Get Info panel

Changed "everyone" setting to "Read & Write" - the other two settings were already set to "Read & Write"

Under the tool icon I used the drop down to "Apply to enclosed items..." and a progress bar started doing that

NOTE: While I was waiting I Googled and came up with a terrible post which said NEVER do this... !!!!

Was panicking until the progress bar finished - thought I'd lost it all.

BUT, fingers crossed, this seems to have worked, just done a backup successfully...

The Time Machine icon hasnt reappeared on the HDD though, just a generic yellow one.

I'll try this on the previous HDD which had this problem and see if it works, nothing to lose really!

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Answer 2

rcosta887

Level 4

3,604 points

May 24, 2019 2:54 AM in response to Joat the cat

There is a chance some type running process is interfering with the drive. You can test this out:

Go specifically into Disk Utility (as opposed to Finder) and try to unmount your external drive. If it unmounts, then go ahead and re-mount it and see if it works now.

If it doesn't mount it will tell you specifically which process is blocking the drive (if that is the root cause of your issue).

If it's an app (such as Word, or Preview, etc.) close that app out and try again. If it's something like Finder or Dock you can Force Quit that process and try again.

If it's still not working it may be some other issue that caused it. Go into Finder and control-click on your external drive and select "Get Info". Unlock the Get Info pane and make sure "Everyone" and "System" is set to Read & Write permission.

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Answer 3

BDAqua

Level 10

250,253 points

May 24, 2019 11:34 AM in response to Joat the cat

Yes, for it to happen so fast is a bad sign... failing drive, interface, cable, interference (USB3 is very prone to interference from Wifi, TV's, Radar, Ovens, etc.

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Answer 4

May 24, 2019 9:05 AM in response to Joat the cat

Joat the cat wrote:

Sadly, it doesn't seem to have worked fully! :(

I can do a manual backup to the time machine HDD but as soon as I switch on automatic backups, it loses the HDD again, very frustrating. I have erased the first disk to fall over and am currently setting up a new time machine backup.

I also found reports about this on various sites going back a number of years - and a few where it happened after a upgrade... go figure!

This would be indicative of a failing drive, much like

Time Machine has completed ... a new backup for you

If you need to create a new backup from Mac.

If that message reappears is very likely the TM backup disk has been operating in a state of failure, and will continue to reappear with increasing frequency. The solution is to replace it.

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Answer 5

Eau Rouge

Level 8

42,656 points

May 24, 2019 11:53 AM in response to Joat the cat

When you buy an external drive, LaCie or other you need to reformat it as soon as you connect it to the Mac, if it is just going to be connected to a Mac then format it as Mac OS Extended (Journaled) on a GUID partition map. If you are going to be using it between a Mac and a windows machine then format it as exFAT on a Master Boot Record partition. The other thing is do not use any of the manufacturers software the drive came with, this just interferes with the operation between the Mac and the drive and is not needed.

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Answer 6

Joat the cat Author

Level 1

8 points

May 24, 2019 11:59 AM in response to BDAqua

I'm just checking out these types of threads "https://discussions.apple.com/thread/7690131" as ALL the top level HDD - see screen grab - are saying the same thing... I worry its the my machine hard drive that is the problem but I'm unable to boot in recovery mode as Command (⌘)-R just wont work for me...

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Answer 7

Joat the cat Author

Level 1

8 points

May 24, 2019 8:46 AM in response to BDAqua

Sadly, it doesn't seem to have worked fully! :(

I can do a manual backup to the time machine HDD but as soon as I switch on automatic backups, it loses the HDD again, very frustrating. I have erased the first disk to fall over and am currently setting up a new time machine backup.

I also found reports about this on various sites going back a number of years - and a few where it happened after a upgrade... go figure!

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Answer 8

Joat the cat Author

Level 1

8 points

May 24, 2019 10:50 AM in response to BDAqua

I waited for the HDD to make a fresh backup (named TM2019) before plugging in the HDD I was having trouble with - not sure which is which now, sorry.

Sadly, even after erasing and making a new backup using Time Machine the original problem persists, the HDD can't be seen by Time Machine BUT you can do a manual backup using the drop down menu...

I'm stumped!

Just ran Disk Utilities on the original HDD I first posted about and have problems with it - see screen grab

I will try and repair it

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Answer 9

Joat the cat Author

Level 1

8 points

May 24, 2019 11:23 AM in response to BDAqua

Gotcha, see attached, it seems like that may be a problem? And thank you for all this help, it is much appreciated.

I have run disk utilities on both external HDD now, seems like the the problem is with the partition map but as I have just erased one of them and then used it for a TM backup, it seems strange for it to have happened so fast...

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Answer 10

Joat the cat Author

Level 1

8 points

May 24, 2019 11:39 AM in response to BDAqua

I thought they were plugged in thru firewire, shows how much I know!

Its odd that the same thing has happened twice in the last 6 months in exactly the same way - Time Machine suddenly decides it can't see the disk, after running fine - but coincidences happen... I will buy a third HDD (possibly not a LaCie Porsche this time!!!

Any externals you find good?

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