Photo previews disappearing & history not showing on edited photos

[tttintti]

Hi! 
So this is a bit difficult issue to explain but I'll try my best, please bear with me. I'm using Lightroom Classic (the newest version) on my Windows PC (Win10). The catalog is stored on my external hard drive because I'm traveling a lot (and using my laptop while traveling) and I want to use the same catalog while traveling. The size of the catalog isn't big - about 15k photos.

Everything has been working fine until I came home the other day, plugged my external hard drive to my PC and it informed me there's a problem. I ignored that, opened LrC to notice that it doesn't show my latest photos on their albums in the library. I checked photos from the harddrive and there were no such albums. I attached the hard drive to my laptop, found the photos and after that they were visible on PC and LrC as well.

Now there's a new problem. Lightroom lost previews of these photos I was working on while traveling. The photos show like this on the library. I have to click each photo individually to be able to see the preview and to be able to edit them. Develop-mode doesn't open the photo if I haven't clicked them 'visible' on Library. 

The other problem is that these edited photos aren't showing the editing when I open the photo on develop-mode. I mean the history is there and from there I can click the latest edit (in this case 'Export-Hard drive) and then all editing is visible. 

Edited photo but showing the RAW

Final, edited image after clicking 'Export' on history. 

This is very problematic and time-consuming for me because I need to export all these photos at once and now LR exports them without the editing if I don't do the procedure described above. Thankfully only few of my photo albums are like this - but they still have thousands of photos in them. 

Any tips how to go around this? And to get previews back.

I'm sorry if my explanation was difficult to understand, I'm not native English speaker. 

[C.Cella]

First of all test the catalog integrity.

Then optimize the Catalog.

After that : Select folder or photos >  Library > Previews > Build Standard-Sized Previews.

If that fails then you can delete all the previews form the HDD and see if generating them anew works.

You can also select all photos and "Read Metadata From File" and see if all the photos finally show the latest version.

Just be sure before reading metada (that is undoable) that to save all the XMPs and keep history for all photos.

P.s.

I suggest to store the catalog on the Laptop itself, if you have a SSD all operations will be faster.

You can keep files in the external HDD.

.

[tttintti]

Thank you @C.Cella ! Your tip to read the metadata from the file actually worked (at least with one album). I tried first to build standard-sized previews but it managed to finish building 6 out of over thousand and stopped there. So naturally I canceled the task. But it seems that reading metadata from the file worked because it brought back the editing and now I can succesfully export the whole album as fully! 

I obviously tested the catalog integrity beforehand and there was no errors in that. I tend to do it each time I'm exiting LR and backing up the catalog. 

P.s.

I suggest to store the catalog on the Laptop itself, if you have a SSD all operations will be faster.

You can keep files in the external HDD.

.

By @C.Cella

I haven't been storing my catalog directly on my laptop because I'm using the same catalog on my desktop. I don't like moving big files like the catalog back and forth between computers but would you recommend doing that instead of storing the whole catalog in the external HDD? I would prefer to use only one catalog at a time instead of many different ones. 

[C.Cella]

@tttintti 

I recommend keep the catalog on the internal storage for performance's sake as I have seen speed improvement when storing catalog internally and on SSD.

Also keep have a copy (up to date) in the HDD + have compressed backups in both.

Yeah a lot of copies but it's safer, you can use sync toy on Windows to keep all copies in sync effortlessly.

If you can't find Sync Toy I think I still have a copy from my windows days.

If you have to move the same catalog across machines then you can use the one on the HDD.

How big is your catalog?

[GoldingD]

/Edited/

Rethinking, and relooking at your screen captures, My reply below the line may be bunk. The remarks by C.Cella are more to point. Appears to be a library previews problem, not a photo location problem.

______________________________________________________________________

The catalog is stored on my external hard drive because I'm traveling a lot (and using my laptop while traveling) and I want to use the same catalog while traveling.

Are both the desktop and the laptop Windows computers?

Do you keep the photos on the laptop within the same folder as the catalog. That is to say in a subfolder in the folder the catalog is in? That keeps absolute paths simple enough so that if that external hard drive is seen on the two computers as different hard drive letters, LrC would still be happy.

[tttintti]

Both the desktop and the laptop are Windows computers, using Win10. All photos are kept in the exactly same locations and the path is the same eventhough I'm using the hard drive on both computers. I've changed the hard drive letter to be the same on both computers to avoid any problems and it has worked fine so far. 

[Sean McCormack]

While @C.Cella is right about performance, your situation requires exactly what you're doing. 

What was the error that you encountered can you remember? 

You say you checked integrity, but I'm not sure that includes the previews database. Optimise, on the other hand, definitely works on it. 

Deleting the previews is a bit extreme, as you'd need to recreate them all again as you go, but it may be the solution..obviously the last thing to try. 

[C.Cella]

@Sean McCormack 

Yes I think you are right, my suggestion is more complex.

@tttintti 

You could consider using buying a SSD if you intent to store you catalog externally.

The photos can be even on HDD the main/only advantage of storing photos on SSD is to speed up import.