Trouble importing photos in Lightroom Classic from Desktop and Downloads folder in OSX

I don't think LR 6 is supported on Catalina. But you should make sure that the acces preferences are set correctly in the System Preferences, Security & Privacy, Privacy tab as below:

I think the last update to LR 6 was LR 6.14 by the way

Hi there,

We are sorry about the issue you are facing while trying to import files from the desktop or other local folders.

Would you mind confirming the macOS version you are using and the version of Lightroom Classic you are using by going to the Help menu > System info?

If you are using macOS Catalina, you can try to add Lightroom Classic to the accessibility list for macOS by going to System Preferences > Security and Privacy > select the Privacy tab. Also grant permissions to Lightroom Classic under Files and Folders then restart the computer to check if that helps.

You can also try granting permissions to Lightroom Classic under Full Disk Access to check if that helps.

You can also try to reset the preferences of Lightroom Classic using the steps mentioned in the link below.

https://helpx.adobe.com/in/lightroom-classic/help/setting-preferences-lightroom.html

Note: Please takes a backup of your presets, plug-ins, etc. prior to resetting the preferences.

Regards,

Nikunj