AI masks in Lightroom Classic is not Working

Graphics Processor Info:
DirectX: NVIDIA GeForce GT 730 (27.21.14.5671)
Init State: GPU for Display supported by default
User Preference: Auto

so GPU driver v 456.71. a newer one exists, v 475.14 released 9 July 2024. See if updating helps.

mind you, a very old GPU, may have limits.

/Followup/

Init State: GPU for Display supported by default

Yes, looks like that GPU will not support the advanced capabilities in LrC. Sometimes a new GPU driver may fix that, typically because a new GPU driver may cause LrC upon startup to reconsider the GPU capability. But yes, that old, not likely.

Please post your System Information as Lightroom Classic (LrC) reports it. In LrC click on Help, then System Info, then Copy. Paste that information into a reply. Please present all information from first line down to and including Plug-in Info. Info after Plug-in info can be cut out as that is just so much dead space to us non-Techs and it takes up vast amounts of scroll space making the reply less readable and less likely that others will bother with your post.

In a first step you should  try to reset the Lightroom preferences.

https://www.lightroomqueen.com/how-do-i-reset-lightrooms-preferences/

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

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

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.