when I open up photos and click on one to enlarge it shows up for a split second and then a large grey triangle with an exclamation mark immediately shows up. How can I enlarge these photos without this happening?

The most likely cause is that the underlying file is no longer available or the library has become corrupted and the link to the photo in the library package is lost.

Presumably you are not able to edit the photo either?

vernonia23 wrote:

thanks Russ..no I haven't but will research on how to clean/speed up.. ..his advice.

I asked about those types of apps because they are bad! Do not try any such apps. They can only make the problem worse.

Under preferences do you have the box ticked that says ‘copy items to library’? If it is ticked yo7 have a managed library

Haven't been able to determine if you've solved your problem. Have You?

If not have you installed or run any "cleaning", "optimizing", "speed-up" or anti-virus apps on your Mac?

Are you running a referenced or managed library? Managed is preferred to prevent this from happening.

To be certain that you do not have any referenced photos you can create a smart album that says ‘photo is not referenced’.

However, as Old Toad says have you solved your bigger problem?