Lightroom error when saving metadata: "Could not write metadata. Unknown file formats." and "photos have read-only access"

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  • Problem
  • Updated 3 years ago
I am running a MacBook Pro with Yosemite, Lightroom subscription (so latest) and keep all images on a Synology DS213j NAS.

If I right click on modified DNG files and "save metadada" it comes up with...
"Could not write metadata. Unknown file formats."

If I keep retrying they eventually go through but then the error changes to
"photos have read-only access"

I don't have the same issue on my PC. I have read-write permission through finder and other apps. I have tried turning SMB and AFP on/ off on the Mac. A local test was fine, so that suggests it is a communication error with the NAS when saving metadata to the DNG.

Occasionally it also gives an error that the file has been changed outside of LR and do I want to bring those in or over-write with LR's metadata. I have seen this issue on other forums, and this one, so was wondering if a solution was out there. Any help much appreciated.
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James Shaw

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  • frustrated

Posted 3 years ago

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James Shaw

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I did a test last night in changing how the Mac connects with the NAS. Rather than connecting in Finder by clicking on the NAS under "shared" devices and then "connect" and putting in username and password I connected by clicking "go" and "connect to server", then mounted the drives instead.

This change in method, which I guess more officially mounts the volumes proved to be a better communication pipe for LR to write the metadata for some reason, even though in my mind I don't see how there's much difference between these 2 modes of connecting to the NAS??

This meant rather than read-only error on half the images, it just did the occasional one. Still it is the occasional one, so that's annoying.

I suspect it's also the Synology NAS indexing files, and briefly taking write-access away from LR. I looked on the server side and when I save the metadata in LR, the process to index those files instantly kicked in on the NAS. It's almost as if it's too fast and cuts LR's write access mid-stream, causing the error. I'll see if I can delay Synology indexing files somehow, or put the RAW images in an un-indexed location to see if this makes a difference.

Still weird that it works on a PC (although that was LR4), but not on a mac. It must be how read-write is dealt with across the different platforms??
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Chris Cox

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That means that there is an OS or NAS server bug.

MacOS 10.9 and 10.10 have had some issues with SMB connections, and many people have better luck using CIFS to connect instead.
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James Shaw

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Cool thanks Chris will try that and report back!
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James Shaw

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Hi Chris. I tried using CIFS, and it was reliable, but impossibly slow unfortunately. I did however have a fair degree of success by using SMB. Before it was set to AFP, and this was not reliable while using LR.
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Chris Cox

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If you are using MacOS 10.10, then please let Apple know about these issues so they can fix the OS bugs.