P: Message: "The catalog could not be opened due to an unexpected error."

@Rikk 

I can't begin to tell you how frustrating this is. I've enjoyed Lightroom for years and now this. I spent all day with a tech in chat and nothing. You guys have a problem as documented here. Please fix it or reduce my subscription to just cover Photoshop.

Having constantly this problem too … only going back to LrC 10.1.1 let me open my catalogues w/o getting the error message.

@Rikk 

I'm piling on here. First time this ever happened was yesterday. Please add me to your list of clients to whom this is happening. I'm running OS 11.1 and have tried earlier versions of LRC to no avail.

This thread at least lets me know that I'm not alone and will have to make do with doing edits of new photographs in PS and Camera Raw. Standing by for a fix, but please reduce my subscription fee by half in the mean time... I never really liked software as a service.

Yes and being stuck in the outdated version of Lightroom has some kinks. The library previews are not the same as viewing them in the edit panel. It’s quite annoying. I would really like to be able to use Lightroom to its full extent and be able to preview my edits in the library module. We need this to get fixed! 

@Rikk I tried your suggestion of renaming the catalog and trying to open the renamed file in v10.2.  I had no success.

@andrew_rodney, I started to try your suggestion, but seemed to have done something wrong on the full catalog export.  

Instead, I tried @Rikk's suggestion of renaming the catalog and trying to open.  I had no success.

Apparently, this has been an intermitant issue for years.

There has been no real solution ever provided! (true?)

There has been no real explanation ever provided! (true?)

Only: Acknowledged

We posters just fade away, I can't hear convinced voices saying how or what action fixed it. All post hoc logic.

Does the issue just goes away ? Just keep clicking to see?

How about a class action for breach of contract?

Cheers, Bill Harris

Have same  "....unexpecred error."

This has been an intermitant issue for years.

There has been no real solution ever provided! (true?)

There has been no real explanation ever provided! (true?)

Only: Acknowledged

We posters just fade away, I can't hear convinced voices saying how or what action fixed it. All post hoc logic.

Does the issue just goes away ? Just keep clicking to see?

How about a class action for breach of contract?

Cheers, Bill Harris

On the older version, if you optimize the catalog, or export as catalog (everything), then try with newer version, any luck?

LrC v10.2 will not open my catalog, same problem I had with v10.1.1.  I roll back to v10.1 and it works perfectly.  I am using a 2017 iMac 27" with Big Sur 11.3 (the problem also existed with the last couple of iterations of Big Sur 11.2).