Lightroom CC: Can't start the app anymore, get this message: Fatal database error at path

you're a hero. I've spent over a week going back and forth with Adobe about this issue and they've been useless. Thank you so so much.

Rikk Thank you so so much ! it helped me too. Thank You !!!!!

Thank you so much!!! this help me a lots.

I JUST WANT TO SAY THAT YOU *** SAVED MY LIFE WITH THIS!!!

[moderator edited for language]

Thank you!

I have the same problem as hal but I'm windowss user!

The instructions for Hal will also work on Windows. 

• Close Lightroom
• The Mcat file is located in users/username/AppData/Local/Adobe/Lightroom CC/Data/(long string)/
•  If you are completely synced, you should be able to rename your Managed Catalog.mcat to Managed Catalog.old 
  
• Launch Lightroom and allow it to resync from the cloud. 

If you are not completely synced you may have to repeat recent edits and reimport recently imported files. 

Good day guys.
Can’t find any of these on my Mac. No pictures folder nor managed catalog.mcat anywhere

THANK YOU!!! 

Mis respetos, muchas gracias. Eres un pro 

OMG, THANK YOU SO MUCH FOR POSTING THIS!!!

Do you know how to delink the original photo that have a previews in the catalog?

Hi!, im having the same problem and i have tried absolutely everything, were you able to solve it?

Hi Lucy,

I was able to dive down into SQLite to open the damaged .mcat Lightroom catalog which is simply a SQLite database with an Adobe-specific extension. This obviously isn't accessible to most people. While I wasn't able to directly access the records in the database, I managed to do an export of the raw database which I then imported into a new SQLite database after removing some of the obvious causes of corruption. A process, I'm surprised no one here or from Adobe ever suggested as a possibility.

Sadly some database indices must have been mangled either when the corruption first occurred or when I tried to restore the database. As far as I could tell most or all of the records from the catalog were present in the database but I doubt the Lightroom engineering team meant for Lightroom to self-repair sufficiently to deal with a database as severely damaged or corrupted as mine. 

It took me a ton of time to go back and forth with Adobe (on the phone, via Twitter, and here) to just talk to someone from the engineering team (I never got that far despite rounds of telephone conversations). In my mind these issues are not really acceptable for a professional product like Lightroom considering the high ticket price of a large storage subscription like mine. Rikk Florh does a commendable service here, but a single community representative is not really the level of service I expect for a product of this category. 

After the last vain attempt I described above and after folks from Adobe kept suggesting restoring a fully cloud synced catalog was the only way to recover from catalog corruption (as a software engineer myself, I find that a bit of a punt, however understandable) I finally gave up, deleted my corrupted catalog since it was extremely large and preventing me from restarting the Lightroom "Classic" to CC migration process from scratch. 

As it had in the past, the migration from a very old Lightroom 2015 catalog first failed with no obvious path to recovery. So I ponied up to pay extra for Adobe's Creative Cloud All Apps plan which does include Lightroom Classic just to be able to upgrade the old Lightroom catalog to the slightly different and space-efficient one. The final catalog size difference between the old CC 2015 version and CC Classic (get your product naming straight, Adobe) was obviously concerning but after some googling around it seemed like this was expected as the new format was slightly more space-efficient. 

The whole re-migration process took over a day since I have over 250,000 shots from nearly 20 years of photography. To conclude this jolly tale, we're not several days later and I only have 80,000 or so shots synced up to Adobe's cloud storage. This means I will live in constant fear of anything going wrong (as it previous did) until all my photos are finally "secure" on Adobe's servers.

Oh, and obviously I lost days of photo edits and people tagging work. Since those were done during my first migration initial sync period, before the corruption occurred (as a result of power loss). 

As a conclusion to anyone reading this and considering Lightroom CC for your precious large libraries of photos: tread lightly. Adobe has an amazing opportunity to do what Apple couldn't with iCloud Photo Library (sync issues, lack of UI performance, inability to handle large libraries) but this current version of Lightroom CC shows a lot of rough edges. As far as I can tell, CC doesn't make catalog backups like the old Lightroom versions did. While this is seemingly more convenient, a blind faith in eventual consistency from a remote cloud storage system is foolish in any situation where customers either don't have a fast upload speed (i.e. multi-day initial sync process) or have large libraries which will result in a long initial sync process regardless of their upload speed. 

I see you've started a new thread - we will respond there.