So I recently started traveling and had to opt for many more portable solutions. I was/am on the hunt for better solutions. Though this is very fresh and new, so I thought I had some time to use this set up and play with it to figure out exactly what my needs and wants are in a more practical solution.

Here is my setup - 2015 Macbook (the tiny one with only use USB C port) running on OSX 10.11.6 El Capitan; USB 3 hub with SD slot; 2 x Seagate 2TB external HDD; Lightroom 6;

Here is my issue - My external HDD with the photos in lightroom, lightroom database and catalogue file(s) on it is no longer mounting when I plug it in.

Series of events leading up to it - The other day I was importing my photos from my SD card to Lightroom and it threw an error about a quarter of the way through. I'm sorry I didn't catch the exact error as I was sorta on the run and didn't think to take better note. Basically it did not finish importing the photos. Lightroom was still running and functional. So I tried re-importing the images. It got further but did the same thing again. So I tried a third time and it didn't even make it to the first one. The external hard drive was no longer reachable.

Here is what I have tried - I unplugged and replugged it back in. It would not even register. I restarted, still could not recognize it. So I tried with just a USB to USB C adapter and not through the port. It still would not recognize it. After many attempts at open DiskUtil to run first aid on it, I stuck it in the freezer and it actually worked after about half an hour. I did not have any other computers to test it on. Though I attempted to run a virtual Linux environment to see if it helped, because they are typically better than mac's at reading external HDD's. I did not get it fully running before I was able to get it working after freezing it. I had to run, so I just crossed my fingers it would hold out until I had more time and internet connection to back this up to something like amazon s3.

Some additional things I can note which may be helpful to know. I have the exact same external hard drive I use for some other storage, and it has no issues through the hub or directly plugged in (with a USB C adapter). Also, "sometimes" I can plug in the hard drive that is giving me issues, and though it does not show up in Finder or Mount to the Desktop, I can open up Terminal and run diskutil list and it shows up. But when trying to manually mount it via diskutil mount /dev/diskN it just hangs.

My Question - I still have lightroom open and running. In fear of closing it and not saving the work I've done. Is there something I can do save the work loaded in lightroom? Maybe plug in my second hard drive that is working and tell it to recreate a new lightroom database file from it's in memory state? (I don't know exactly how lightroom works or if that is possible).

Further Question - Do any of you have recommendations on steps to take once this is recovered to not end up in the same situation again? Maybe further reading? Anything? Also, under the circumstances I am not able to make any kind of recover from this failed hard drive, what is the recommended path to reconcile any work or minimize my lossage? For example: is my still currently open running lightroom able to produce a new database file in a new location?

  • \$\begingroup\$ Are your USB hard drives hub-powered, or do they have power bricks? What is the USB hub model you are using (is it a USB-C hub, or is traditional USB-A, and using the USB-A-to-USB-C adapter)? Is the hub port-powered, or wall powered? \$\endgroup\$
    – scottbb
    Commented Feb 11, 2017 at 16:12
  • \$\begingroup\$ The hard drives are hub powered. The usb hub is a USB-C hub, and it is not wall powered. Though, I have tried the external hard drive ( USB-A ) with an adapter to make sure it was not the USB hub. It did not seem to make a difference. \$\endgroup\$ Commented Feb 12, 2017 at 2:38
  • \$\begingroup\$ You don't mention if your photos are on the external drive, or just the catalogue. \$\endgroup\$
    – LC1983
    Commented Feb 21, 2017 at 9:44
  • \$\begingroup\$ @LC1983 the photos and the catalogue file(s) are on the external hard drive. \$\endgroup\$ Commented Feb 22, 2017 at 20:28
  • \$\begingroup\$ Take Lightroom out of the loop first by seeing if you can read the drive from the operating system directly. If you can, copy the files and then import from there. If not, then there is probably nothing to do but buy better drives next time. \$\endgroup\$
    – Itai
    Commented Jun 24, 2017 at 2:13

4 Answers 4


I expect that you'll get a "Lightroom encountered an error ..." message and it will want to quit - it doesn't offer an option to save the catalogue database to alternative storage.

If the Mac sees the disk, but can't mount it try repairing it in DiskUtility - if that fails, I've been successful at recovering corrupted HFS+ volumes using TestDisk

A second copy (local or cloud) is helpful for recovery in the event of catastrophic disk failure, but don't confuse it with a real backup solution (the operation of updating a "backup" copy is almost certainly going propagate hidden problems to the backup copy (e.g. deleted or corrupted files)).

If you have the upload bandwidth, a cloud backup solution (I use Crashplan) is the best option, but it does need very decent bandwidth and doesn't work if you switch your machine off (very rough figures: 1Mbit/s up is 10s/MB, so 10000s/GB … roughly rounded up 3 hours/GB … 1TB would take 3000 hours … 125 days (24x7)).

In terms of LR, I'd always recommend enabling the "Automatically write changes into XMP" - the possible performance hit is worth it for the safety net of recovering metadata in the event of corrupting the catalog.

  • \$\begingroup\$ Thanks for the suggestion of TestDisk, I will check it out. I have tried with DiskUtility, but since it can't even mount it, it doesn't even show up in DiskUtility. Also thanks for the suggestion of Crashplan. I will add this to the list of cloud backup solutions. The "Automatically write changes into XMP"; what exactly does this do? Can it recover metadata when you can't get to the pictures and/or the catalogue file? \$\endgroup\$ Commented Feb 22, 2017 at 20:31
  • \$\begingroup\$ The Lightroom metadata is primarily in the database (some of it can only live in the db - collections, etc.), but keywords and develop settings are stored in the XMP - rebuilding a corrupted catalog from XMPs would be so much better than nothing (or better still, recover using a backup catalog and then refresh from the XMPs). \$\endgroup\$ Commented Feb 24, 2017 at 11:58
  • \$\begingroup\$ The XMPs are intended to make the metadata accessible to external applications (e.g. Bridge). Basically, if you enable it you'll get a .XMP with every raw file as a safety net for a lost/corrupted catalog, but you still need the image files (and .XMPs). \$\endgroup\$ Commented Feb 24, 2017 at 12:06

I can help with the disk recovery part as I helped a friend with a similar issue a few months ago.

I ended up putting the external drive on a Linux box and using ddrescue against the drive to aggressively try to recover the whole drive. This could take days. You'll need 2TB of free space somewhere to write the disk image. I used the commmand:

ddrescue -vv -d -S /dev/sdX image.out image.log

where sdX is your drive's path on Linux.

In my case I still had an unmountable image, so I then ran PhotoRec against the recovered image to recover the images:

PhotoRec searches for known file headers. If there is no data fragmentation, which is often the case, it can recover the whole file. PhotoRec recognizes and recovers numerous file formats including ZIP, Office, PDF, HTML, JPEG and various graphics file formats. The whole list of file formats recovered by PhotoRec contains more than 480 file extensions (about 300 file families).

This will not recover your Lightroom DB, as I am sure it is fragmented.

Prevention? As someone mentioned in another answer, also save the XMP's along with the images, and I give a very hearty 2nd recommendation for CrashPlan. They even have a free option where you backup to your own remote system -- although you really should have an "offsite" backup as well in case of fire, flooding, or theft.

Note: Looks like both ddrescue and photorec are also able to be run directly on MacOS


I can only really help with the further question part.

I also run a 2015 MacBook with Lightroom for when I'm on the road. I keep the catalog file locally on the MacBook, but back it up weekly to an external hard drive. I also use Time Machine to back up the MacBook.

  • \$\begingroup\$ interesting. I am curious to know of other ways to possibly set up Lightroom with external drives. What I mean is; I had the catalogue file on the external hard drive along with the photos. Maybe I should put the catalogue file locally and just have the photos on the external drive? To your point, you still probably want to back up that catalogue file locally to the cloud or somewhere else. \$\endgroup\$ Commented Feb 22, 2017 at 20:37

The good news is that if you don't hear any grinding, the data on disk is probably okay. The bad news is that recovering the data probably won't be cheap.

There's a small possibility that the problem is with the USB enclosure rather than the hard drive itself, in which case if you open the enclosure, remove the hard drive, and put it in a different USB enclosure, it might work.

Unfortunately, it's probably a cold solder joint somewhere on the actual drive's circuit board, in which case the repair isn't something you can readily do yourself, though if you can figure out what part needs to be cooled down, you might be able to use aerosol freon or similar every minute or two to keep that part cold enough to keep it running long enough to pull the data off of it.

  • \$\begingroup\$ I wouldn't say "small possibility." USB is, by nature, a race-to-the-bottom sort of technology. You don't get a choice between good and bad USB drive enclosures, you get a choice between barely adequate and unsuitable. Thunderbolt is better, not so much for the better technology, but because the higher parts costs needed to operate in that space pushes out most of the junk vendors. Thus you get $200+ Thunderbolt enclosures and $20 USB enclosures, when the extra costs of implementing Thunderbolt don't account for all of that $180 difference. The rest is in improvements across the board. \$\endgroup\$ Commented Aug 23, 2017 at 4:42
  • \$\begingroup\$ I'm not saying "switch to Thunderbolt," at least not in the context of the question, since the OP's laptop doesn't have such a port. What I am saying is that swapping the enclosure has a pretty good chance of fixing the problem, particularly if he tries a unit with good reviews. But, I've been burned there, too: I once had a new enclosure write megs and megs of junk to the disk; the problem went away on switching to a different enclosure. \$\endgroup\$ Commented Aug 23, 2017 at 4:44
  • \$\begingroup\$ Usually, if an enclosure fails, the device won't show up at all. If the drive shows up as a device (which it does, according to the question), that means that the computer is successfully talking to the USB-SATA bridge and the bus bridge can see a hard drive attached (the drive is getting 5VDC and the data lines are working). That doesn't 100% rule out the enclosure, but it makes it very unlikely unless the enclosure's controller is somehow wedging. \$\endgroup\$
    – dgatwood
    Commented Aug 23, 2017 at 16:26
  • \$\begingroup\$ That said, there are certain bits of very broken silicon that have bugs where they stall for a long period of time on bad blocks. So if there are bad blocks involved, you might have better luck pulling data with a device that has a native (non-USB) SATA controller, e.g. a spare SATA or eSATA port on a computer. \$\endgroup\$
    – dgatwood
    Commented Aug 24, 2017 at 16:10

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