Unable to launch Lightroom Claissic Error: ?:0: attempt to index field '_nglController' (OS Not Provided, Lightroom Classic Version Not Provided

Hi ​@photogreg17120772 

Sorry to hear you’re running into this. Errors like this often happen when preferences or a plugin are interfering with launch. The first thing I’d recommend is resetting Lightroom Classic preferences: Reset Preferences - Lightroom Classic. Please use the manual method after creating a backup of your preferences.

If that doesn’t help, could you also share:

• Are you on Windows or macOS?

• What Lightroom Classic version are you using?

• Did this start after a recent update or plugin install?

• Does the error appear before any catalog opens, or only with one specific catalog?

All of this information will help us investigate the issue further and assist you accordingly.