Please help fix hard drive!


macrumors newbie
Original poster
Sep 19, 2019
Hi all,

I could really do with your expert knowledge right now, I would be beyond grateful, I've been freaking out a bit :/

So yesterday I was working on a photoshop file I keep saved on an External HDD, nothing unusual, but after I saved the file and quit photoshop I navigated to the file's directory and noticed the drive was acting up a bit, the file kept appearing and disappearing, so I ejected the drive, restarted and connected the drive again and nothing. I've read and even experienced myself so many instances where drives just pack up and they're basically done for so my heart dropped at this point because I basically have my whole (digital) life on this drive. I'm no genius but I have a fair bit of knowledge when it comes to computing so I have got somewhere in fixing it but not completely.

So the drive is still showing in disk utility but the partition is greyed out so I can't run first aid on it but on my old macbook running mavericks I am able to but it just gives 'Invalid B-tree Node Size' error. So from there I ran Disk Warrior to try and rebuild the catalog but it's not found everything. I've screenshot to show, when I go to details on the drive it shows 729MB free, 1,961,065 files total (I know it was nearly full). When I run the rebuild it says 609GB free, 1,894,697 files total.

I'm not too familiar with rebuilding the catalog on a drive, if I proceed with replacing the damaged catalog will it wipe 600GB of my data?

Any advice would be appreciated, thanks!


Last edited:


macrumors 6502
Nov 30, 2013
Backup, backup, backup... It is too late for you now, but all disks will eventually fail. Hardware, software, connection, communication,.... If data are important, backup is our only way to protect them. Especially external disks should be routinely back up using some sensible solution. External drives are connected through quite unreliable connections with connectors and cables - and have also less reliable source of power than internal drives.
My experience with fixing disk errors is kind of spotty - may be 50-70% chance of fixing structural errors (on HSF+ you have, much less on APFS). And very low chance of recovering from hardware errors.
Now, here is what I would do if I were you at this moment - and I am sure you will get other (and different) advise also. I would first get the same size disk as you have (4TB) and clone (make exact copy) of the current disk using hardware disk duplicator (~$40 on Amazon). For that you need to extract the disk from enclosure, which may (or may not) be easy. By using disk duplicator you clone bit by bit and make exact copy of failed disk (with all failures) without needing any os to read/touch the failed disk.
After this I would let Disk Warrior "fix" the disk and recover the files. If it works, great. If it does not, re-clone the failed disk again, and try some other tool. The trouble is, that you have basically only once chance to get the fix right. And if the fix fails, your chances of fixing it after the failed fix are even smaller than before.
The trouble is, that you need new 4TB disk and disk duplicator, around $200 of hardware and time.


macrumors P6
Feb 20, 2009
OP wrote:
"my heart dropped at this point because I basically have my whole (digital) life on this drive..."

Well... can't you just go to your backup drive?
(there is a message here... do you get it?)

Try this:
a. Power down, all the way off
b. DISCONNECT the external drive for a moment
c. Power on the Mac
d. Once you get to the finder, RE-connect the external drive, and...
e. Just wait a while. See if the finder will try to mount it and correct any minor directory problems.
f. Give it 30 minutes.

Does this get you anywhere?


macrumors newbie
Original poster
Sep 19, 2019
Thanks for the replies guys.

I know I know I really should have a backup but it's costly, especially in my case, that's why I haven't. To get another 4TB hard drive and have it in a RAID set up, and as you can see I was running out of space so I was already looking to get another drive for further storage, plus I have a couple of other drives with data (I work with a lot of large files and store a lot of data) I would literally need 8 hard drives to have a backup for each.

I've always stuck to 2.5" portable externals because of the convenience but I've been thinking to maybe get a massive 10TB or 12TB desktop external and then when I can afford to, buy another as a backup drive. I've also been looking into cloud storage, particularly BackBlaze, apparently it's $6 a month for unlimited storage.

Anyway as for recovering the data, Fishr I've tried that, no luck. Honza I was thinking that also. If there was a way I could see what is missing so I could at least see whether it's important stuff but I'm just going off my memory at the moment of what I remember of the file structure.