I lost recent photos in photos library on external drive

Wow! First-- have you searched for them? I mean, they might not be where you think. They should appear near the end of the Recents view, but in the Library view they may be misplaced because they have a wrong date. If you have pictures of a rabbit (wildlife!), then try doing a search for Rabbit and see if some pictures show up.

How did you import the pictures to Photos-- with a cable? Did you see the pictures in Photos after the transfer? For instance, it's possible to see the pictures on the Import screen, but then accidentally fail to push the import new pictures button. Are you sure that they got imported? Did you put them in an album?

Were these from your iPhone, or were they from a camera, or what? Did they come from an SD card?

Making a backup copy is excellent, but the unfortunate thing is that you may be backing up mistakes. As a thought, Mac's Time Machine does backups every day and keeps them for weeks and months. But this might not have helped if they never got copied at all.

Let us know what you find...

newappleid wrote: Maybe I just need to mourn what I lost?

Probably so.

Let me again put in a plug for Time Machine. It does an incremental backup-- but it only records (each hour!) what has changed. So you do the first backup, and it has everything; then the next backup is very small, and so on. It keeps the hourly backups for a day, and keeps daily backups for a month, and weekly backups until the drive fills up. Then it replaces old backups with new ones. So you can go back to last week or last month and see your computer just as it was then! Since I do lots of stuff on my laptop away from home, I plug it in when I get home and it immediately and automatically starts a backup with me doing nothing. Having had hard drives go kaput in the past, I use two for this.

There are other backup systems that do similar things. Time Machine is free with a Mac.

For my Nikon, I plug in the SD card and copy the files to a folder on my Mac's internal drive. (That will be backed up by the TMs.) I don't ever delete from the SD card. I then copy the pictures from that folder to Photos. I keep the last two months of pictures on my internal drive, so I transfer the previous month folder to join the rest of them on an external drive. When the SD card fills up (maybe 4000 pictures), I copy the images to a separate hard drive (this is now a 3rd of 4th or maybe 5th copy) and re-format the SD cad.

For my iPhone, which has more casual pictures of family on it, I rely on iCloud to copy pictures to the Mac (and thus the two Time Machines.)

I really don't want to lose two months of pictures!

I'm a bit confused about Time Machine ... So you are using that for the folder that you import your photos to on your computer, vs. using Time Machine to back up the photos library?

Time Machine backs up the whole computer. (You can also have it backup external drives, as well, but I don't.) So it backs up the Photos Library on my Internal drive and folders of documents and pictures that I have on the computer. In addition to two Time Machine drives (older, mechanical drives-- they don't have to be fast), I have a separate SSD drive (very tiny and fast) that I carry around that has stuff I might need but which won't fit on the 1 TB internal drive. I back it up periodically.

When you say "I then copy the pictures from that folder to Photos" do you mean the photos library?

And where are you keeping that?

I have the folder of recent direct-from-camera pictures on my laptop's internal drive, and I keep the Photos Libraries on my laptop. The laptop drive is 1TB and, with me adding pictures all the time, it keeps getting too full. That's why I carry around an extra (tiny!) drive. It's 2 TB and smaller than 2 thumb drives. Since all the pictures have gone through folders on my internal drive, they are backed up by Time Machine. But I don't carry the (larger) TM drives around, so I have this little SSD in case I want other stuff.

I said "copy to Photos" rather than to the Photos Library, because that's how you get pictures into the Libraries-- you use the "Import" menu in Photos. (Or drag the pictures to the Photos Icon.) We never interact directly with the Libraries.

I used "Libraries," plural, because I have several Photos Libraries. I've been scanning old family pictures, trying to figure out who they are and what the relationship is. After scanning, I don't edit them much, so I keep them in a separate Library. I have another for work pictures. I have another one for pictures that are pretty old, so they don't change much. And the Library that does change is the "Favorites" Library that has the best of all those-- pictures that I'd like to see on my phone or iPad and might show to friends and family. I copy the best ones into the Favorites Library, and that Library is the one that I connect to my phone and iPad using iCloud Photos.

I have 24,000 photos in my library. (probably could delete at least 2000 of those -)

I pretty much decided that I don't delete pictures. Even the blurry ones. You know, they take up any physical space, like the closet full of years of old prints I have. A 2 TB hard drive can hold maybe 200,000 pictures in the same physical space as 2,000 or 20,000 pictures. I've spent some time going through old images, and I found that even bad ones could have some information on them-- maybe remind me who was there or what happened around that time.

I'm showing my not very tech savvy self in my confusion, so thanks again!

Not at all. I swear, the hardest thing is dealing with all the information we're bombarded with. Computers were supposed to help with organizing all that, but they seem to just pour on more stuff to organize.