LIGHTROOM CLASSIC DEBRUITAGE

Did you select a raw file? AI Denoise only works with raw files, not jpeg.

Unfortunately you haven't given us any information about your system. Therefore, all proposed solutions are a look into the crystal ball. Also describe the error in more detail.

Do you get an error message?

What are you trying to do?

What do you like to get and what happened?

Which are the steps to reproduce the issue.

If possible please post a screenshot on which we can see the issue.

Is your system up-to-date? Do you have installed all recent updates and patches for the operating system and the device drivers, especially the graphic driver. If you have a NVidia graphic card installed, make sure that you are using the recent Studio version of the driver, not the Game Ready version.

Please provide a copy of your 'System Info'. This can be get from the LrC Help > System Info menu item. There's a copy button in the System Info dialog. Press this button and paste the info into your next forum post.

One thing you can try. Do a reset of the preferences of Lightroom Classic:  How to reset Lightroom Classic preferences (adobe.com)

It's recommended to backup your preferences before you reset the preferences to the default settings: 

https://helpx.adobe.com/lightroom-classic/kb/preference-file-and-other-file-locations.html