I hope this is the right place to ask. I just discovered a problem with some of my photos and I'm not sure the cause. First a little background. I have four drives (one working, three backups) that I use to store my photos. They're essentially duplicates of each other. Two stay onsite and the other two are distributed to separate locations. After a shoot, all photos (NEF) are copied from the XQD/SD cards to each drive, i.e. the files go from the original source to each drive. All photos are then processed through Lightroom from the working drive. "Processed" meaning they're culled, flagged, developed and keyworded. The best photos get run through Photoshop for some final processing. Once a month or so, all drives are run through Chronosync to synchronize XMP and PSD files created from the processing routine. To make the Chronosync process faster, I usually start new Chronosync documents for each year. Well, I haven't done a full drive synchronization in a long while but since I knew I had gone back and reprocessed some older photos with LR, I decided to do drive-wide synchronization.
Drive-wide synchronization is where I discovered two problems. First problem is that I have a group of vacation photos from May/June 2016 that have one file size on two drives and a different file size on the other two drives. A "get info" command shows a size difference of about 12,635 bytes. The smaller file shows dimensions of 0 x 0, no color space metadata and no color profile under the more info tab of "get info" while the larger shows the info (5568 x 3712, RGB and Adobe RGB). (Screenshot attached.) Clearly the smaller files have lost some metadata.
The only thing I might be able to attribute this to is when I was on vacation, I used Photo Mechanic on the now smaller files. The two drives affected are the drives I had with me and used PM on. I used PM for cropping, picking/flagging, the IPTC stationary pad. That, however, wouldn't affect the NEF files as PM doesn't write to the files. But it does when you have another problem. When I got back to my other drives, backed up the files and later ran Chronosync, there was a creation/modification date mismatch. I think the mismatch was due to time zone changes i.e. original files with PDS time stamps copied to drives A & B in PDS time zones and to drives C & D in CDS time zones. Anyway, I used PM to fix the creation/modification dates on the copies that I had with me on the trip but not on the ones that stayed home or vice versa (sorry, 2-1/2 years ago). Since Chronosync had already done it's thing, I hadn't run a sync on them since.
The second problem that I have no explanation for is that I'm getting random photos that have an extra attribute. Chronosync is showing file #1 on Drive A with no extra attribute and file #1 on Drive B with an extra attribute or vice versa. It's usually the whole folder of images but completely random affecting a few hundred files over fifteen years. The extra attribute is usually "com.apple.quarantine". Again, in almost all cases, each file is copied directly from the card to the hard drive so I'm not sure how this is changing. From what I've read, the com.apple.quarantine attribute is usually attributed to files that have been downloaded and triggers the "the file you're attempting to open is from the internet, are you sure you want to open it" dialog or something like that. I'm completely lost how my own photos would acquire that attribute.
Any help or explanation on either problem would be greatly appreciated. Thanks.
