Can see but not change metadata.

[richb46]

The Buttons 'Target Photo' and 'Selected Photos' are greyed out (see pict).  Lightroom Classic v. 12.3, on MacBook Air M2 using MacOS Ventura 13.4. I am using two screens - the standard lightroom window on my external screen, selected image on MacBook Air screen. The images (25,000) are on an external disk.  All folders and images are set with read/write permission for anyone. 

In Library mode, selecting an image brings up EXIF and IPTC data for that file. I can enter Title or Caption for that image, but then selecting another image and returning to the first shows that my typing was not recorded. (I can add keyword tags) This suddenly happened two days ago. My captions are sometimes lengthy - giving history of object.

[Rikk Flohr: Photography]

You have to select more than one photo to activate those buttons. 

[richb46]

Thank you Rikk - you are correct - the buttons activate when more than one is selected. And a dialog box appears if I have chosen 'selected photos' asking if I want to set metadata on multiple images.

But my title or caption entry is still not retained.

[richb46]

More details - Lightroom Classic behaves as if it is recording my entry (title or caption) - even remembering an entry and suggesting it when I start entering data for a different image. But nothing entered shows up in the metadata pane. I've tried creating a new catalog and importing the old one into it. That fails at  ~17,000 images (out of 25,000) because the program encountered an (unspecified) error.

[richb46]

more detail - the metadata window has a spinning wheel in the upper left as if the program can't find the relevant file, once I attempt to change it.

[Rikk Flohr: Photography]

A spinning wheel means that LrC is currently reading the Metadata from the photos selected. If many photos (thousands) are selected, this can take a while. 

I routinely update metadata for tens of thousands of images and do not see issues other than read time for the initial selection.  You might try using other than EXIF & IPTC as your default view - especially if the data you want to change can be found in a different view.