Corrupted Lightroom Catalog: saw message stating it needed to download the catalog from Onedrive....

[Dr. McCoy]

When I opened Lightroom a couple weeks ago, I saw a mesage pop up briefly stating that the Lightroom Catalog needed to be downloaded from Onedrive, displaying a download status bar that showed about 50% I believe.

I did not know that my catalog was being stored on Onedrive, and that the copy from my computer was being removed.

I have not been able to open the catalog, nor find the catalog anywhere.  It was a rather large catalog at that point, containing eight months+ of work and tens of thousands of photographs, and would have been a few tens or even hundreds of gigabytes.

Some questions:

1. Might anyone else have seen this issue or something similar? What did you do to resolve it?

2. Is it a known issue?

3. Is it recommended that one use Onedrive to back up the Lightroom Catalog?

4. What might be the best way to find or restore the Lightroom Catalog?  Is it possible that it was corupted both at Onedrive and on my computer?

Thank you!

[Dr. McCoy]

P.S. I am using Windows 10 on a new i9 Thinkpad.

[DdeGannes]

Follow the advise from thedigitaldog

You also need to be aware Lightroom Classic needs the Folder that contains your Catalog file, Previews data file and other data files stored in that folder, in addition the original image files also have to be physically connected to your Computer via internal drive or external drive and not in a Cloud storage. I do not use One drive but am aware there is an option to retain original files on your device.

[TheDigitalDog]

The best approach is restore from a back up (ideally one you make on a regular basis). 

You have a backup right? 
If the catalog is really corrupted, there is a very slim possibility that if you contact Adobe directly, they might offer to repair it, with no guarantees. But the best solution is to go back to your last backup and simply replace that catalog. And ideally, you backup every day! 

[dj_paige]

Placing the Lightroom Classic catalog file in a folder that is "synchronized" with some cloud storage service (Google Drive, DropBox, OneDrive, etc.) is generally frowned upon as it is known to cause the occasional catalog corruption.