Photos: The Library could not be opened.

getrealbro

macrumors 6502
Original poster
Sep 25, 2015
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I’ve been setting up our Mini for two users logged in at the same time (one using the Mini and the other remotely logged in via VNC). While testing this setup I encountered the following error message when opening some of of the Photos libraries on an External drive.

Library could not be opened.
The library “xxxxx” is in use by another program.
[Open other] [Quit]

After a bit of experimentation I realized that this message occurred when one user was trying to access the Photos “System Library” of the other user. It appears that Photos in Mojave “locks” each user’s ‘system library’ even when it has been closed and Photos is not active.

So I created dummy Photos “System Libraries” for each user, so that both users could access all of the Photos libraries on the external drive (20 libraries - 1.5TB).

FWIW a similar message would occur with Photos in El Capitan -- but only if the other user was actively using that library, even if it was the other user's "system library".

GetRealBro
 

getrealbro

macrumors 6502
Original poster
Sep 25, 2015
274
89
Another Mojave Photos quirk…

Once a Photos Library is ‘updated’ by Photos in Mojave, its Modified Date in a Finder window becomes useless. Because it looks like Time Machine changes the Modified Date on almost every hourly backup, even when the Photos app has not been active for a long time (e.g. over night).

FWIW it’s a little weird to see the Modified Date for 5 Photos Libraries change to the same time, at the same time. BTW the Modified Date of the Photos Libraries that have not been updated, do not change.

GetRealBro

Edit: Just to make these Modified Dates changes more interesting… the Mojave and El Capitan Photo libraries are in the same volume (on an external drive) that has always been excluded from Time Machine backups in Mojave.
 
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getrealbro

macrumors 6502
Original poster
Sep 25, 2015
274
89
The “Date Modified” for the dozen+ Photos libraries on my external disk gets weirder every day. This Finder list view is the best yet.

Date Modified.jpg

Note the Date Modified of all but one of these Photos Libraries is exactly the same time, about one hour before the capture. It would be pretty hard to open, modify and close that many libraries in less than a minute. :cool: But the best part is that the only library I’ve actually opened and modified today is the one that says it was last modified yesterday.:rolleyes:

GetRealBro
 

getrealbro

macrumors 6502
Original poster
Sep 25, 2015
274
89
Another Mojave Photos quirk…

Once a Photos Library is ‘updated’ by Photos in Mojave, its Modified Date in a Finder window becomes useless. Because it looks like Time Machine changes the Modified Date on almost every hourly backup, even when the Photos app has not been active for a long time (e.g. over night)....
The case of the Ever Changing Modified Date….

I think the Modified Dates of the Photos Libraries are changing, even when I haven’t opened/modified them, because Photos is still scanning these 1.5TB of libraries for “faces”, etc. in the background. Why the modified dates frequently coincide with a Time Machine backup is still a mystery. But maybe TM interrupts these background process, causing them to time stamp the library.

FWIW I shoot a lot of nature photos. And what Photos decides is a “face” is almost always comical. I wish I could just turn off facial recognition.

GetRealBro